*3.3. Group SC*

The rats weighed 317.9 ± 19.9 g (*n* = 7). Data from one rat (the first) was excluded from the study as it was administered an initial SC dose of medetomidine of 0.1 mg/kg and became apnoeic for approximately 2 min, requiring external chest compressions. The seven subsequent rats were administered a lower dose of 0.05 mg/kg SC medetomidine and anaesthesia was uneventful. The blood glucose concentration peaked at 120 min at 20.4 ± 3.4 mmol/L (Figure 1).

The inhaled isoflurane concentration required to maintain an adequate depth of anaesthesia throughout the procedure in Group SC was more variable than in the other groups (Table 1). The serum medetomidine concentration peaked at 60 min at 3.4 ± 0.9 ng/mL (Figure 2).

**Figure 2.** Time course of mean (±standard deviation) serum medetomidine concentration after subcutaneous administration of 0.05 mg/kg medetomidine in six Sprague-Dawley rats.

### *3.4. Pharmacokinetic Calculations*

The pharmacokinetic and pharmacodynamic parameters were calculated from the mean serum medetomidine concentration data (Table 2). To achieve a target medetomidine concentration of 14.4 ± 3.0 ng/mL an initial SC dose of 0.12 mg/kg medetomidine followed by a SC infusion of 0.08 mg/kg/h medetomidine should be administered during isoflurane anaesthesia.

**Table 2.** Individual and mean (±standard deviation) pharmacokinetic (PK) and pharmacodynamic parameters after administration of 0.05 mg/kg SC medetomidine in seven Sprague-Dawley rats. *Cmax* = maximum serum concentration; *tmax* = time of *Cmax*; λz = elimination rate constant; *t1*/*2*β = elimination half-life; *AUC0*→∞ = area under the serum concentration time curve from time = 0 to ∞; *Cl* = total body clearance; *Vdarea* = volume of distribution at pseudo-equilibrium; LD = loading dose; MD = maintenance dose.

### *3.5. Trial of Results*

Two additional rats were administered medetomidine with isoflurane at the doses calculated in this study. The vapouriser setting for isoflurane could be maintained at or below 0.5% and anaesthesia was uneventful. Given the calculated initial dose was higher than that used in groups SC and IV the

initial dose was administered over five seconds to mitigate the risk of apnoea (as observed in the IV group and the first rat in the SC group that was administered 1.0 mg/kg SC). Apnoea did not occur when the initial dose was delivered over five seconds.


**3. Discussion**

RTT is a progressive postnatal neurodevelopmental disorder; three individual genes, *MECP2*, *CDKL5*, and *FOXG1*, have previously been thought to be the cause of its variants with the altered *MECP2* as the major contributor. Later, it was suggested that RTT is a monogenic disorder caused by either null mutations or mutations that alter the MBD or NID functions of *MECP2* [15,16,47]. MBD and NID facilitate the binding of MeCP2 to modified cytosine in chromatin and recruitment of the NCOR-SMRT complex, respectively; their combination is vital for MeCP2's role as a repressor [48,49]. The altered forms in the other two genes which were previously characterized as variants of RTT were designed as distinct disorders with several overlapping symptoms to RTT. The three proteins have similar extensive amount of disordered regions and play important roles in the brain. The disordered structure itself is a unique property in protein that may contribute to the interaction with a diverse binding partner and the versatility of a protein. While the three proteins may show similar symptoms in the altered form, the investigation on their similarity in the molecular basis remains scarce, particularly on the disordered structure properties and their binding partners. Focusing on RTT, we investigated the evolution of their disordered structures and their binding partners through prediction and phylogenetic profiling, respectively. This approach is important to give an insight into the similarity of biological systems of those proteins structurally and evolutionarily, which may provide useful information for the development of a RTT therapy strategy. RTT itself has attracted considerable attention as its causative protein displays features related to epigenetics and have been shown to have partially or fully disordered structures.

All three proteins have been experimentally determined to play roles and are abundant in the brain, especially the MeCP2\_e1 and hCDKL5\_1 isoforms [50,51]. It is confirmed by the emergence of neurological impairments in the altered availability or forms of either protein. Through evolutionary analysis and IDRs properties, we provide an additional point of view for that feature. Phylogenetic profiling analysis of MeCP2, CDKL5, and FOXG1 and their interacting proteins showed that 240 molecules formed four clusters—i.e., chordates, metazoans, multicellular, and eukaryotes. Among the three, only *FOXG1* was a member of Class 2, which comprises genes acquired during metazoan evolution, whereas the acquisition of *MECP2* and *CDKL5* was correlated with chordate evolution. The acquisition of *CDKL5* and *MECP2*, and *FOXG1* may contribute to the development of the chordate brain and metazoan nervous system during evolution, respectively. Additionally, order–disorder structure predictions revealed that all three proteins had order–disorder structures that were relatively conserved across chordates. Human MeCP2, CDKL5, and FOXG1 phosphorylation sites were also shown to be relatively conserved to chordates. IDRs properties provide proteins with more interaction areas and PTMs sites, spatiotemporal heterogeneity of structure, and ability to associate and dissociate easily with binding partners. Hence, proteins with long IDRs are likely to have a capacity to bind to many different partners. Accordingly, all three proteins were shown to have multiple binding partners, and FOXG1 and MeCP2 displayed the highest number of partners, some of which were evolutionarily acquired before the metazoan evolved. By cooperating with various proteins partners, particularly the co-repressor complex, FOXG1 or MeCP2 can modulate the expression and suppression of different genes [15,52]. The co-repressor complex itself denotes a conserved mechanism that manifests in diverse forms and may have several functional entities depending on the context in which they are recruited [53]. This indicates the necessity to regulate either FOXG1 or MeCP2 concentration precisely; otherwise, altered availability is likely to be deleterious. Several studies have shown that either overexpression or under-expression of MeCP2 and FOXG1 corresponds to neurological deficits; this phenomenon may not independent from their co-repressor complex that has been showed to play roles in neurogenesis and neuron maturation for FOXG1, and MeCP2, respectively [7,15,52]. On the other hand, CDKL5 binds to a fewer number of proteins that have functions in regulating cell adhesion, ciliogenesis, and cell proliferation. We hypothetically suggest that the amount of CDKL5 binding partners is underestimated since this protein was predicted to have relatively long disordered regions with many constrained

disorder features and phosphorylation sites; it also has fewer insertions and deletions than either MeCP2 or FOXG1 along the evolution.

FOXG1 is a transcriptional factor playing an essential role in ventral telencephalon development; it serves as a hallmark of the telencephalon in vertebrates [52,54]. Among the 237 Class 1 or 2 genes, 233 were detected in the cerebral cortex, with nine expressed at a high level (Figure S2). Seven genes were acquired during metazoan evolution, of which four and three encode MeCP2- and FOXG1-interacting molecules, respectively. Since FOXG1 was also acquired during metazoan evolution, acquisition of FOXG1, SATB2, and SALL1 may have played essential roles in development of the neocortex. FOXG1 is transiently expressed in neuronal progenitor cells and regulates their migration to the cortical plate [55]. During this process, FOXG1 expression is upregulated, which contributes to cortical plate development [56]. Similarly, the FOXG1-interacting chromatin remodeling factor SATB2 was found to be expressed in the cortical plate and regulates neocortical development [54,55]. Therefore, it is conceivable that transcriptional co-operation between FOXG1 and SATB2 mediates the laminarization of the neocortex. In support of this possibility, patients with the SATB2 mutation exhibit an RTT-like phenotype [57,58]. There is no direct interplay reported for MeCP2 and FOXG1. The causative regions in the altered form of these proteins that result in the development of RTT or RTT-like disorder exhibited similar functions in regulating the other genes' expression, but likely via a distinct pathway. We suggest that FOXG1 is not a potential target for developing treatment for RTT. However, induced pluripotent stem cell (iPSC)-derived neurons generated from FOXG1+/− patients and patients with MECP2 and CDKL5 mutations reportedly exhibited a similar increase in synaptic cell adhesion protein orphan glutamate receptor δ-1 subunit (GluD1) expression; this result indicates the need for further study to reveal the mechanism of each protein and might be implicated in the clinical symptom overlap among FOXG1-, CDKL5- and MECP2-related syndromes [52,59,60].

CDKL5 belongs to the same molecular pathway of MeCP2. MeCP2 was acquired during chordate evolution; a prerequisite for this step was the acquisition of MeCP2-interacting molecules such as ZNF483, SOX2, HIPK2, and HIST2H2A. The MeCP2 kinase HIPK2 was shown to be required for the induction of apoptotic cell death in neuronal and other cell types via phosphorylation of the MeCP2 N-terminus [61]. Given that CDKL5, another MeCP2 kinase was also acquired during chordate evolution; it is possible that HIPK2 and CDKL5 cooperate to activate MeCP2 during neocortical development. Since apoptotic cell death increased in *Cdkl5* knockout mouse brain, CDKL5 probably has a suppressive function in the apoptosis process in contrast to HIPK2 [62]. Therefore, functional division of their kinases through phosphorylation of MeCP2 is an important issue. Indeed, the CDKL5-interacting domain was shown to be associated with the C-terminus of MeCP2 [63]. Hence, CDKL5 may phosphorylate the carboxy terminus. Thus, both HIPK2 and CDKL5 may activate MeCP2 by phosphorylating different regions of the protein. It has been suggested that MeCP2 also suppresses CDKL5 transcription and that CDKL5 overexpression may also contribute to the typical RTT symptoms [64]. Hence, aiming the catalytic domain of CDKL5 as the key target for developing alternative strategies to treat classical RTT may be essential since its sole impairment resulted in some symptoms that overlapped with those of classical RTT. Additionally, the CDKL5 disordered region, which spans after the catalytic domain to the C-terminus, is suggested to have many SLiMs. The linear motifs theoretically help to determine the various fates of a protein including subcellular localization, stability, and degradation; these motifs are also able to promote recruitment of binding factors and facilitating post-translational modifications [26,38]. Since these motifs typically regulate low-affinity interactions, they can bind to molecules with different structures of similar affinity and facilitate transient-binding, which are favorable properties for drug targets. Accordingly, this region appears to be a potential target for classical RTT treatment. However, this should also consider the expression levels of CDKL5 which are highly modulated spatiotemporally [64,65].

IDRs show unique properties within protein which challenges the traditional viewpoint of the protein structure paradigm. They have differences in residue composition, intramolecular contacts, and functions to ordered regions which cause different evolutionary rates. Generally, they evolve

more rapidly than ordered regions, owing to the different accepted point mutations. However, some disordered regions can be highly constrained as they may play crucial roles and have multiple functions; assessing the evolutionary rate of IDRs may thus reveal crucial protein-specific amino acids in the biological system [66]. In this study, we found a unique relationship between evolutionary rates of disordered regions and symptoms of a disease caused by FOXG1. The N-terminus residues of FOXG1 are highly variable and constrained to be disordered, while the residues from FBD to the C-terminus are constrained and contain an ordered structure. It has been reported that mutations in the N-terminal are more likely to be associated with severe phenotypes, and mutations in the C-terminal are associated with milder phenotypes [52]. We reported and predicted a phosphorylation site located in Ser 19 to be conserved in chordates even though it is located among flexible disordered regions; casein kinase 1 (CK1) modifies this site and promotes the nuclear import of FOXG1, which corresponds to neurogenesis in the forebrain [67]. This explains that a flexible disordered region can retain its functional module from phosphorylation, despite harboring numerous insertions and deletions, and that severe phenotypes may result from the altered function of Ser 19 of FOXG1.

Among 236 male testis expressing RTT-related genes, 47 genes expressed at a high level. Because paternal-derived de novo mutation has been shown to affect X-linked MeCP2-related female Rett syndrome [6,68], paternally expressing mutation in these genes may affect the sperm-derived genetic and/or epigenetic inheritance that influence the cause of Rett syndrome in a daughter. Further studies are required to analyze these possibilities.

It is important to remember that the features of structural order–disorder and phosphorylation sites in this study have been inferred using linear sequence predictors and that the sequences and mutation points were retrieved from databases whose data have been collected from studies with various methods. It should be considered that we use canonical isoforms instead of predominant brain isoforms, this option may be able to be applied computationally but should be of concern experimentally. This study provides suggestive or hypothetical conclusions, thus further experimental study is important to verify the findings of this study. Ultimately, the results can still be used and considered as a basis for further identification.


**1.1 Paradigm shift in anthropomorphic manipulator design**

The very nature of human anatomy presents a unique challenge in the replication of the human hand. Mechanical engineering approaches rely on the expectation that the artificial hand design approach is quantifiable. The following reasons provided by [1] providing insight as to why mimicking the human body is not a straight forward process.

#### *Biomechanical Design Principles Underpinning Anthropomorphic Manipulators DOI: http://dx.doi.org/10.5772/intechopen.105434*

For these reasons quantifiable methods are hard to realize. In reality, working in the space of anthropomorphic manipulator design becomes subject to engineer/ designer best practice or previously knowledge. This reality often lends to this chapter, will express the value of a paradigm shift by exploring the biomechanical and physiological design principles that contribute to anthropomorphic manipulator design. The chapter concludes with a set of defined grasps that are a direct result of the design paradigm shift.

#### **1.2 Current state**

To this point in time, the human hand has been the "golden standard" of function, versatility and dexterity in grasping tasks as proven by the ongoing attempts to artificially recreate it [2]. Mimicking the qualities and properties of the human hand has always been a lofty and hard to realize goal, however, due to the current technological advancements of our age we are closer to achieve it than ever before. For these reasons this research is progressive, of great value and exciting. The ability of an artificial hand to function in an unmodified human environment directly relates to its capacity to function like the human hand. Traditional approaches to artificial hand design have been susceptible to ignore and/or omit the organic biological features of the human anatomy that are essential to hand function. Recent trends are tending toward artificial hand design that includes multidisciplinary viewpoints that consider more than just traditional mechanical principles.

In artificial hand design it is important to consider the Degrees of Freedom (DoF) the hand possesses. The DoF of a system is the number of independent parameters that define its configuration. The reviews [3, 4] describe some of the available electromechanical hands currently on the market [5–16]. Each review supports the general view that as the DoF of an artificial hand increases so does its anthropomorphism and function. Research into modeling the human hand claims that 24 DoF accurately represents the posture and movement of the human hand (including the wrist) [17]. There is consensus around this point with most literature agreeing that the human hand has between 21 and 26 DoF depending on whether you include or exclude the wrist [18]. The difference in DoF between studies can also be attributed to the DoF associated with the carpal bones of the hand and whether or not they are included.

Latter attempts at hand design employ the idea of bio-mimicry or an approach that is human inspired. The focus of these types of hands are on the tendinous structures actuating the hand and their synergies with ligaments, joints and actuators [4] approaches artificial hand design by mimicking the human bones and joints of the hand. Naturally, this makes for an esthetically pleasing design. In contrast to this approach a bulky unnatural looking wrist was implemented in the design and was recognized as required improvement [19] builds upon the idea of biomimicry by developing artificial tendinous structures that mimic the human hand and by improving the design of artificial thumbs. Their approach was esthetically pleasing and functioned well. Within their approach there was a new idea to incorporate joint capsules at each joint. Further studies [1] in the same year presented work on mimicking the mechanics and material properties possessed by the human hand and incorporating them into working artificial prototypes. The work presented herein emphasis the synergistic tendon networks, bone configuration, bone orientation, and joint development that are required in artificial hand design. It is expected that these types of approaches will increase in popularity and improve as the research climate and time allows.

#### **2. Joint stabilization**

The following section addresses the connection that exists between hand function and artificial ligament design. Firstly, it is important to understand how the bones of the human hand lay a foundation for the ligaments to layer on. The bones on which hand ligaments are inserted provide ligament pathways on which joint stabilization relies. Incorrect placement of ligaments severely effects the way a bone moves, transfers force and thus can drastically reduce the function of a hand. The bones of the human hand are essential to hand function, however, without the stabilizing ligaments and tendons they are of little use. Each joint of the hand has a series of ligaments that limit undesirable movement and protect the hand against excessive force. Hence, joint stabilization by virtue of the biological layers present in the human hand are integral to hand function.

Joint stabilization is integral to hand function; therefore, it is important to unpack the role and location of the ligaments responsible for finger joint stabilization and movement. In particular, the following section describes and defines the collateral ligament, the volar plate, and the annular ligament. Each ligament is then put in context by applying them to the design shown in **Figure 1**. We begin by explaining the collateral ligament and follow that by exploring both the volar plate and annular ligament.

#### **2.1 Collateral ligament**

This section describes the artificial collateral ligament by defining suitable insertion locations of the ligament for each phalanx of the hand that optimizes the movement between adjacent bones. The collateral ligament acts as the primary stabilizer of phalanx joints and is responsible for connecting bones. Taking the index finger as an example we name and orient the bones of the finger in **Figure 2**.

Determining the insertion positions of the collateral ligament on the artificial proximal phalanx (**Figure 3**) is defined by two features. These features are: The phalanx length, LP, and the centroid, c. the phalanx length, LP is the summation of LBC and LHC while the centroid is found through the CAD software SOLIDWORKS using the mass property evaluation.

The coordinate system is established on the centroid of the phalanx. The phalanx length and the location of the centroid determine the ligament insertion locations IH and IB. LB and LH define the limits that bound the insertion locations. The coordination of the head insertion IH and base insertion IB are given by

$$I\_H = (\mathbf{x}, \mathbf{y}) = ((L\_{HC} - L\_{HI}), (\mathbf{y} < \mathbf{0})) \tag{1}$$

**Figure 2.** *Index finger bone configuration and orientation.*

*Biomechanical Design Principles Underpinning Anthropomorphic Manipulators DOI: http://dx.doi.org/10.5772/intechopen.105434*

#### **Figure 3.** *Collateral ligament insertion points.*

and

$$I\_B = (\mathfrak{x}, \mathfrak{y}) = ((-L\_{BC} + L\_{BI}), (\mathfrak{y} < \mathbf{0})) \tag{2}$$

Where *LBI* and *LHI* are determined by a ratio of the total phalanx length, *LP*, that is still acceptable for correct bone interaction between each phalanx. The values for *LBI* and *LHI* are determined by a joint motion test. Insertion points are designed and modeled at distances between 3 mm and 8 mm from each end of the involved phalanx. Joint motion is quantified by a rating between one and three. Where one represents a good range of motion and three represents a poor or severely lacking range of motion. Any insertions below 3 mm or above 8 mm do not provide any range of motion and do not add contribute to the motion of the joint. (Values for *LBI* and *LHI* are found by dividing the insertion distance by the phalanx length). As shown in Eqs. (1) and (2) the location of the insertion in the vertical direction is governed by the variable, *y*. If, *y* ¼ 0 the insertion is located along the *x*-axis. If *y*<0 the insertion is located below the *y*-axis. If the insertion is governed by ð Þ �*y* then it has two insertion points either side of the *y*-axis. The three insertion location conditions are expressed by the following equations:

Condition (1) is expressed by

$$(\mathbf{x}, \mathbf{y}) = ((L\_{\rm HC} - L\_{\rm HI}), (\mathbf{y} = \mathbf{0})) \tag{3}$$

Condition (2) is expressed by

$$(\mathfrak{x}, \mathfrak{y}) = ((L\_{\text{HC}} - L\_{\text{HI}}), (\pm \mathfrak{y})) \tag{4}$$

Condition (3) is expressed by

$$(\mathbf{x}, \mathbf{y}) = ((-L\_{BC} + L\_{BI}), (\mathbf{y} < \mathbf{0})) \tag{5}$$

For ease of application **Table 1** below outlines the conditions applicable to both the head and base of each phalanx.

Any major variance from the values and conditions listed in this table are detrimental to the joints range of motion and its stabilization. Through this method

#### **Table 1.**

*Insertion location conditions assigned to each phalanx.*

**Figure 4.** *MCP and PIP joints including their ranges of motion.*

collateral ligament insertion is generalized for all artificial hand design. The geometry of the bones in the hand compliment the collateral ligaments at each bone-ligament interface. Collateral ligament placement determines joint function and therefore hand function. Bone surfaces are congruent and possess depressions or protuberances that give clues to ligament insertion locations. The bone surfaces also permit human like range of motion at each joint. **Figure 4** shows the resulting range of motion, *μ* for the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints.

The resulting range of motion of the artificial MCP and PIP joints sit within two degrees measurement of their natural human counterparts, meaning digit function and dexterity are maximized. The collateral ligaments are vitally important to hand function, however, as recognized at the beginning of this section there are three main ligaments responsible for joint stabilization. The next section will look at the remaining ligaments which are the volar plate and the annular ligament.

#### **2.2 Digit joints**

The collateral ligament represents one of the three stabilizing ligaments of the joints of the fingers. This section will describe the role and placement of the volar plate and the annular ligaments with respect to the previously described artificial collateral ligament. The combination of these three ligaments make up the joints of the finger and work in harmony to provide the function and dexterity of the hand. The collateral ligament provides lateral stability and is represented in the black box **Figure 5**. The insertions are achieved via an extruded cut through the proximal phalanx and abide by the conditions stated in **Table 1**.

In synergy with the collateral ligament is the volar plate. The volar plate functions to protect the fingers against hyperextension with its insertion points highlighted in the red boxes of **Figure 5**. These insertions are found on the palmar side of the

*Biomechanical Design Principles Underpinning Anthropomorphic Manipulators DOI: http://dx.doi.org/10.5772/intechopen.105434*

**Figure 5.** *The stabilizing ligaments of the MCP joint.*

**Figure 6.** *The stabilizing ligaments of the PIP joint.*

metacarpal head and the palmar side proximal base. A properly function volar plate limits rotation about the joint and absorbs excessive force placed on the joint in unwanted directions. It can most easily be thought of as a limiter of unwanted movement.

An artificial sagittal band is incorporated into the design of the artificial hand (yellow box of **Figure 5**). Although the sagittal band and the collateral ligament share insertion locations their functions are very different. The sagittal band creates a pathway for the extensor tendon responsible for force transferral and finger extension. It also eliminates transverse tendon slippage. In addition to the sagittal band the hand incorporates annular ligaments. These ligaments share insertions with the volar plate. These ligaments are light in color but outlined by blue boxes in **Figure 5**. The combination of these ligaments allows abduction/adduction and flexion/extension at the MCP joint. The lateral movement in the MCP joint is limited through the placement and angle of the collateral ligaments while rotation is limited by the volar plate. If designed correctly the congruence provided by the geometry of the bones allows smooth movement through the flexion and extension movements of the joint. The concave/convex relationship between the bones also allows abduction and adduction.

The PIP joint (**Figure 6**) connects the intermediate and proximal phalanges. The PIP joint on its own is a planar manipulator capable of only flexion and extension and just like the MCP is stabilized by the collateral ligament (black box **Figure 6**).

The palmar side of the PIP joint houses the volar ligament. The insertion points of this ligament are outlined in **Figure 6** by red boxes. This ligament functions to protect the joint from hyperextension and shares an insertion with the annular pulleys. The PIP joint provides simple planar movement that allows the hand to grasp and manipulate objects with precision and force. Bone geometry and size naturally limits the unwanted motion inherent in the joint, allowing a natural moving and anthropomorphic esthetic.

The final joint of the finger is the distal interphalangeal (DIP) joint. This joint connects the intermediate and distal phalanges. The DIP joint is a copy of the PIP joint described above.

#### **2.3 The carpometacarpal joint**

The thumb has traditionally been an incredibly hard appendage to mimic and replicate artificially. On its own the thumb is the single largest contributor to hand function and dexterity. It is what sets humans apart from the rest of the animal kingdom. With these sentiments in mind it is important to consider the biomechanical makeup of the thumb and incorporate it within the design process.

The Carpometacarpal (CMC) joint of the thumb provides the hand with complex multi-axial movement. The reason for this is the complex geometry of the trapezium bone and its relationship with the metacarpal of the thumb. Artificial ligaments provide stabilization for the CMC joint of the thumb on the artificial hand. The five artificial ligaments are based on the human counterparts and are described below.

The Anterior Oblique ligament (**Figure 7**) is the first of the stabilizing ligaments of the thumb. T1 represents the trapezium bone while M1 indicates the metacarpal bone of the thumb. The anterior oblique ligament functions to limit unwanted movement that would cause the CMC dislocation. The ligament connects the metacarpal bone and trapezium bones. The insertion points are highlighted in red.

In addition to the anterior oblique ligament there is the second stabilizing ligament shown in **Figure 8**. This ligaments function is to stabilize the joint and to limit the movement between the thumb and the palm. As shown, this ligament is inserted near

**Figure 7.** *The anterior oblique ligament of the CMC joint. (palmar view).*

*Biomechanical Design Principles Underpinning Anthropomorphic Manipulators DOI: http://dx.doi.org/10.5772/intechopen.105434*

#### **Figure 8.**

*CMC joint and its artificial ligaments (dorsal view).*

the base of the index metacarpal and the thumb metacarpal (insertions are highlighted in red).

Ligaments three, four and five are artificial replications of the dorsal deltoid shaped ligaments. These are also stabilizing ligaments and are named the dorsal radial ligament, the dorsal central ligament and the posterior oblique ligament. These ligaments share an insertion on the trapezium bone and are connected the surface of the metacarpal bone of the thumb. Each ligament inserts at different points along the metacarpal surface to provide the thumb with a considerable range of motion. All three ligaments contribute to allowing and restricting of movement within their respective three-dimensional spaces. These three ligaments are shown **Figure 9** and are highlighted in red.

The previously mentioned ligaments work in synergy to stabilize the thumb joint and create the base on which the CMC joint relies for function. Along with the complex geometry of the bones at the CMC join these ligaments are responsible for the complex multi-axial movement of the thumb.

This and previous sections have conveyed one possible approach to joint stabilization in artificial anthropomorphic manipulators. The following section will now move into the actuation of these joints by tendons.

#### **3. Tendinous structures**

Movement of the human skeleton originates from the transferral of forces between it and its associated tendon/muscle. This is especially important for understanding hand movement as each minute movement can be attributed to the actuation of a

muscle or tendon. This section approaches the biomimicry of this process by separating the complex movement of the hand into two. Firstly, the tendons that control the fingers and secondly, the tendons that control the thumb.

### **3.1 Finger tendons**

The finger has two primary movements and two minor movements. The primary movements are flexion and extension. The extensor tendon straightens the finger while the flexor tendons bend the finger. The minor movements of the finger are called adduction and abduction. These movements are induced by the contraction and elongation of the palmar interossei muscles. In order to understand the movements of these tendons and how they transfer force into the bones we need to look at their insertion points. We start by outlining the insertions of the extensor tendon. The first insertion is on the distal phalanx and the second is on the intermediate phalanx. These positions are highlighted in the red boxes in **Figure 10**. After its insertion on the intermediate phalanx the extensor tendon splits. This split helps to engage the finger in abduction and adduction. Artificial sagittal bands control the extensor tendon pathway as shown in **Figure 10** (white boxes) and prevent transverse slipping of the

*Biomechanical Design Principles Underpinning Anthropomorphic Manipulators DOI: http://dx.doi.org/10.5772/intechopen.105434*

#### **Figure 10.**

*The pathway and insertion points of the extensor tendon. (Dorsal view).*

tendon. The flexion of the fingers in the hand are actuated by the Flexor Digitorum Profundus (FDP) tendon.

These FDP tendons traverse the palmar side of the hand and insert at the distal phalanx of each finger. The following section will outline the tendons of the thumb responsible for the thumb function, movement and anthropomorphism.

### **3.2 Thumb tendons**

The thumb is a masterpiece of mechanical complexity and is capable of producing complex multi-axial movement. It is essential to understand its basic anatomy and function. Four main tendons are responsible for this movement.

The design and function of these tendons are described in the next section.

The artificial FPL shown in **Figure 11** (left-hand side) is channeled through the carpal tunnel and directed toward the base of the thumbs distal phalanx where it is inserted. The APL also shown in **Figure 11** (right-hand side) inserts into the thumbs metacarpal on the radial side and provides the thumb with abduction at the CMC joint.

**Figure 12** (red boxes) below shows the insertion points of the EPB and the EPL. The EPB inserts into the thumbs proximal phalanx. This tendon is responsible for

**Figure 11.** *The artificial FPL and APL insertions of the thumb. (Palmar view).*

**Figure 12.** *The artificial EPL and EPB insertions of the thumb.*

extension and abduction of the thumb at the CMC joint. The EPL is channeled through the rear of thumb and inserts at the tip distal phalanx. The EPL allows complete thumb extension whereas the PB can only provide partial extension.

It is through a complex synergy that the above-mentioned tendons provide the complex multi axial movement including flexion, extension, and circumduction.


*Study Limitations*

This study was carried out among women in central and northern Uganda, and results may not be applicable to all communities of Uganda. We believe, however, that the findings are possibly illustrative and indicative of experiences of women who go through child marriages across Ugandan communities.


**1. Introduction**

278 Urinary Incontinence

Trigo Rocha F, Gomes CM, Mitre AI, Arap S, Srougi M. A prospective study evaluating the

Venn SN, Grennwell TJ, Mundy AR. The long-term outcome of artificial urinary sphincters.

Vilar, FO et al. Periurethral Constrictor in Pediatric Urologic: Long-term Follow-up. *Journal*

Webster gd & sherman ND. Management of Male Incontinence Following Artificial Urinary

urodynamic and surgical outcomes. Urology. 2008 Jan;71(1):85-9.

Sphincter Failure. *Current Opinion in Urology*, v. 15, p. 386-90, 2005.

J Urol 164: 702-6, 2000.

*of Urology*, v. 171, p. 2626-8, 2004.

efficacy of the artificial sphincter AMS 800 for the treatment of postradical prostatectomy urinary incontinence and the correlation between preoperative

> Urinary diversion is a detour of the urinary tract. It may be necessary in different scenarios and can either be continent or incontinent, catheterisable or orthotopic. Pathological situations which may demand a urinary diversion are varied and include anatomical, physiological, congenital and traumatic causes, e.g. urethral stenosis and partial or complete urethral disruption; bladder dysfunction secondary to radiotherapy or congenital pathologies (posterior urethral valve, Prune-Belly Syndrome, epispadias, bladder extrophy, cloaca); neurogenic bladder and idiopathic bladder dysfunction [1-3].

> The treatment has essentially four main goals: preservation of the upper urinary tract, urinary continence, adequate reservoir emptying and avoidance of urinary tract infections [4]. With the continued development of less invasive treatments for almost all urological pathologies (including severe bladder dysfunction) surgical urinary diversion can be currently considered the end treatment for these patients [2,4,5].

> Urinary diversion can be classified as either continent or incontinent. Continent urinary diversion refers to a reservoir which can be emptied through clean intermittent catheterization (CIC). Incontinent diversion refers to situations where a continuous free urinary flow through an interposed intestinal segment pours into a collecting bag [2].

> Although being a realistic alternative to treat patients with a compromised bladder or urethra, one must be aware of the inherent challenges and possible complications related to urinary diversion. This encompasses not only the surgical aspects, but also the post operative care and management of complications.

> We review pre and post operative aspects related to the continent urinary diversion commonly used in benign pathologies and the current literature pertaining to this.


*Article* **A Systems Thinking Approach to Designing Clinical Models and Healthcare Services**

#### **Inas S. Khayal 1,2**

Received: 29 October 2018; Accepted: 14 March 2019; Published: 24 March 2019

**Abstract:** Chronic diseases are on the rise, increasing in number and treatment regimen complexity. Consequently, the needs of patients with chronic diseases are increasing and becoming more complex and multi-faceted. Such chronic conditions require addressing not only the physical body, but also psychosocial and spiritual health. The healthcare delivery system, however, organically organized into departments based on physical organ systems. Such a configuration makes it ill-suited to provide comprehensive multi-faceted healthcare services that span multiple departments and specialties (e.g., podiatry and endocrinology for diabetes; primary care and psychiatry for behavioral health; and palliative care physicians, chaplains, and social workers for end-of-life care). To deliver new services, the medical field typically designs new clinical models to base its new services on. Several challenges arise from typical approaches to designing healthcare services and clinical models, including addressing only single conditions, describing models only at a high-level of abstraction, and using primarily narrative documents called text-based toolkits for implementation. This paper presents and uses systems thinking as an alternative strategy to designing clinical system models and healthcare services to alleviate many of the current design challenges in designing integrated services for chronic conditions. An illustrative example taking a clinical model and describing it as a system model is presented.

**Keywords:** systems thinking; systems engineering; healthcare system design; clinical models; socio-technical system; model-based systems engineering


Preface

Chapter 8 **How Deep Should You Squat to Maximise a Holistic Training**

**Hypertrophic and Mechanical Evidence 155**

Morse, Adrian M. Burden and Keith Winwood

Chapter 9 **Surface Electromyography in Sports and Exercise 175**

Chapter 10 **Evoked EMG Makes Measurement of Muscle Tone Possible by**

Chapter 11 **Underwater Electromyogram for Human Health Exercise 213**

Chapter 13 **Simulator of a Myoelectrically Controlled Prosthetic Hand with**

**Graphical Display of Upper Limb and Hand Posture 269** Gonzalo A. García, Ryuhei Okuno and Kenzo Akazawa

**Complementary Treatment in Chronic Disorders of the Inferior**

B. Padilla-Fernandez, A. Gomez-Garcia, M. N. Hernandez-Alonso, M.B. Garcia-Cenador, J. A. Mirón-Canelo, A. Geanini-Yagüez, J. M.

Koichi Kaneda, Yuji Ohgi, Mark Mckean and Brendan Burkett

R. A. R. C. Gopura, D. S. V. Bandara, J. M. P. Gunasekara and T. S. S.

Hande Türker and Hasan Sözen

**Analysis of the H/M Ratio 195** Satoru Kai and Koji Nakabayashi

Chapter 12 **Recent Trends in EMG-Based Control Methods for**

Chapter 14 **Biofeedback with Pelvic Floor Electromyography as**

Silva-Abuin and M. F. Lorenzo-Gomez

**Assistive Robots 237**

**Urinary Tract 287**

Jayawardane

**VI** Contents

**Response? Electromyographic, Energetic, Cardiovascular,**

Gerard E. McMahon, Gladys L. Onambélé-Pearson, Christopher I.

During a long perios of time, clinical neurophysiology has expanded and developted new fields.However, the number of specialists of clinical neurophysiology is still limited. Wellqualified and detailed books or monographs on this field are in demand. Contribution of the authors from different countries who are sharing their experience and their own data will increase the attention and focus on clinical neurophysiology.

I am pleased to contribute to the book, "Electrodiagnosis in New Frontiers of Clinical Re‐ search" edited by Dr Hande Turker who I know personally and I have followed her aca‐ demic progress for long time. I had the opportunity to work with her in our Department of Clinical Neurophysiology. She is always full of original ideas and the curiosity that science demands.

In this book chapters relate to different aspects of clinical neurophysiology. I am sure that the book will cover an important necessity of clinical neurophysiologists.

**Gulseren Akyuz, M.D., Professor** Department of Physical Medicine and Rehabilitation and Clinical Neurophysiology Marmara University School of Medicine Istanbul, TURKEY


*4.2. Sub-Question (2): What Do Such Initiatives Perceive as Their Objectives, Barriers, and Achievements?*

According to the charter of the *Latin American Network for Fair, Democratic and Sustainable Cities* (agreed upon in 2011), member initiatives have five common objectives: (i) to monitor a city's situation in terms of quality-of-life, social justice, democracy, and sustainability; (ii) to promote civic participation; (iii) to monitor and influence public policies; (iv) to promote space for dialogue between civil society, the private sector, and the state; (v) to disseminate information and knowledge for informed civic participation and decision-making processes. In terms of target groups and strategies, the sampled initiatives developed a range of priorities. Whereas virtually all (95% of survey respondents) considered elected officials a main target group, about 60% also targeted researchers and staff in public institutions. As a Peruvian respondent (PE#03) explained, "The work

is in stages. We are giving priority to young people through actions and training. The media is getting information and workshops, just as the technical personnel of the institutions, the latter primarily on indicator issues. Social leaders are convened; we sign institutional agreements".

Since (indicator) data represent the lifeblood of initiatives, their availability and reliability are a main concern in some countries. In Bolivia, a respondent (BO#1) explained that "there's very little access to information. Normally we gather it from sources such as interviews and focal groups". In neighbouring Chile, "the official statistics generally have high fidelity" (CH#2). At an aggregate level, 7% of survey respondents in 2014 considered data obtained from national sources as having no or little reliability, and even 28% thought so of data from local sources. The former, however, are often not usable at the local level; as an Argentine respondent (AR#5) explained, "we were unable to access disaggregated data in our locality".

To explore barriers and bottlenecks, the survey contained questions about the prevalence of difficulties in several areas—out of these, finding suitable staff and media attention was not considered problematic by most respondents. Over 50% of them, however, reported significant difficulties in accessing indicator data and finding funding (for running costs and specific projects). Further, on a survey question about political pressure or interference (in relation to areas of work, research, positive and negative news, and involved personnel), 38% of initiatives indicated suffering from them "frequently" or "very frequently"; only a third did not experience pressures. Sometimes this was experienced as a matter of evolving trust—in the words of one Peruvian informant (PE#3), "At the beginning of our activities, there was mistrust of our institution and it was accused of having a political overtone this on the part of the municipal authorities and also in some cases of civil society". In other instances, however, maturing initiatives felt increasing heat. A Brazilian informant (BR#5) stated, "We are going through a period of great political pressure from the current municipal public administration".

Achievements are largely intangible and hard to measure. To quantitatively assess to what extent initiatives were effective in achieving name recognition, the 2014 survey asked respondents to estimate which percentages of three target groups knew the initiative's work; the reported averages were 26% for the city's general population, 49% for relevant technical staff of public institutions, and 72% for decision-makers such as the mayor and councillors. Regarding the latter, individual responses ranged from 1% to 100% between fledging and mature organizations. It is worth mentioning that some indicator initiatives assess their name recognition via surveys, and also have reliable ways to monitor their interaction with office-bearers if they are invited to present quality-of-life survey results in, say, a municipal council meeting. As a Colombian informant (CO#3) explained, "The percentage of the population was measured in our citizen perception survey [...]. Among decision-makers, everyone knows us because we constantly interact with them, either requesting information or at different round tables".

Regarding other outcomes, key informants reported evidence of effects (in some cases backed up by detailed explanations in annual reports) in various dimensions. In terms of conceptual use and influence, 77% of survey respondents indicated having contributed to the development of capacities among public institutions. As a Peruvian respondent (PE#03) stated, "We have achieved that information-generating institutions, as well as public institutions, disseminate their information and try to update it [as] municipal public servants are finally understanding the importance of data". Regarding instrumental use and influence, 72% of initiatives (according to the survey) reported having had some—and 30%, even "very large"—achievements in influencing the design of public policies. According to a Colombian respondent (CO#8), "We made recommendations on the elaboration of the municipal development plans [and] 20% of our recommendations were accepted". A major achievement for many initiatives—especially in Brazil and Argentina—was also the successful lobby for new bylaws introducing a legal obligation for mayoral candidates to create action plans with targets for various sustainability indicators, about which the

elected mayor then has to report back in public accountability meetings; such bylaws are known as "plan(o) de metas" in Spanish and Portuguese [35]. By nature, the cluster of political–symbolic uses and influences is the most intangible; one economic way to assess them is through subjective perceptions of key informants and proxy indicators such as media coverage. Over 90% of survey respondents reported that their initiative had contributed to the city's agenda, public discourse, and knowledge. As an Argentine informant (AR#3) observed, "if by impact we understand that the issues are debated or published, we have had important achievements since in general, the information that we produce is published by the main media outlets".


**Numerical Modelling of Ballistic Impact Response at Low Velocity in Aramid Fabrics**

#### **Norberto Feito 1,\* , José Antonio Loya 2 , Ana Muñoz-Sánchez 3 and Raj Das 4**

Received: 4 June 2019; Accepted: 22 June 2019; Published: 28 June 2019

**Abstract:** In this study, the effect of the impact angle of a projectile during low-velocity impact on Kevlar fabrics has been investigated using a simplified numerical model. The implementation of mesoscale models is complex and usually involves long computation time, in contrast to the practical industry needs to obtain accurate results rapidly. In addition, when the simulation includes more than one layer of composite ply, the computational time increases even in the case of hybrid models. With the goal of providing useful and rapid prediction tools to the industry, a simplified model has been developed in this work. The model offers an advantage in the reduced computational time compared to a full 3D model (around a 90% faster). The proposed model has been validated against equivalent experimental and numerical results reported in the literature with acceptable deviations and accuracies for design requirements. The proposed numerical model allows the study of the influence of the geometry on the impact response of the composite. Finally, after a parametric study related to the number of layers and angle of impact, using a response surface methodology, a mechanistic model and a surface diagram have been presented in order to help with the calculation of the ballistic limit.

**Keywords:** aramid; impact; computational techniques; finite elements; mechanical analysis


**1. Introduction**

urement of low-phase-noise microwave signals. *Journal of the Optical Society of Ameri‐*

[4] Ilchenko, V. S., Yao, X. S., & Maleki, L. (1999). High-Q microsphere cavity for laser stabilization and optoelectronic microwave oscillator. *Proceedings of SPIE*, 3611-190.

[5] Volyanskiy, K., Salzenstein, P., Tavernier, H., Pogurmirskiy, M., Chembo, Y. K., & Larger, L. (2010). Compact Optoelectronic Microwave Oscillators using Ultra-High Q Whispering Gallery Mode Disk-Resonators and Phase Modulation. Optics Express .,

[6] Schliesser, A., & Kippenberg, T. J. (2010). Cavity Optomechanics with Whispering-Gallery Mode Optical Micro-Resonators. *Acta Avances in Atomic Molecular and Optical*

[7] Salzenstein, P., Tavernier, H., Volyanskiy, K., Kim, N. N. T., Larger, L., & Rubiola, E. (2009). Optical Mini-disk resonator integrated into a compact optoelectronic oscilla‐

[8] Tavernier, H., Salzenstein, P., Volyanskiy, K., Chembo, Y. K., & Larger, L. (2010). Magnesium Fluoride Whispering Gallery Mode Disk-Resonators for Microwave Pho‐

[9] Salzenstein, P., Cussey, J., Jouvenceau, X., Tavernier, H., Larger, L., Rubiola, E., & Sauvage, G. (2008). Realization of a Phase Noise Measurement Bench Using Cross Correlation and Double Optical Delay Line. *Acta Physica Polonica A*, 112(5),

[10] Salzenstein, P., Cholley, N., Zarubin, M., Pavlyuchenko, E., Hmima, A., Chembo, Y. K., & Larger, L. (2011). Optoelectronic phase noise system designed for microwaves photonics sources measurements in metrology application. Proceedings of SPIE .,

[11] Anritsu (2000). Typical datasheet Anritsu 69B serie available on page at the following link: http://cem.inrets.fr/private/materiel-labo/images/m\_011\_doc\_gene\_65ghz.pdf

[12] Salzenstein, P., Hmima, A., Zarubin, M., Pavlyuchenko, E., & Cholley, N. (2012). Op‐ toectronic phase noise measurement system with wideband analysis. *Proceedings of*

[13] Salzenstein, P., Pavlyuchenko, E., Hmima, A., Cholley, N., Zarubin, M., Galliou, S., Chembo, Y. K., & Larger, L. (2012). Estimation of the uncertainty for a phase noise optoelectronic metrology system. *Physica Scripta* [T149], 014025, http://dx.doi.org/

[14] GUM: (2008). Guide to the Expression of Uncertainty in Measurement, fundamental reference document. , JCGM 100: (GUM 1995 minor corrections) http://

www.bipm.org/en/publications/guides/gum.html (accessed 5 June 2012).

tonics Applications. *IEEE Photonics Technology Letters*, 22(22), 1629-1631.

*ca B*, 25(12), 2140-2150.

348 Optoelectronics - Advanced Materials and Devices

18(21), 22358-22363.

tor. *Acta Physica Polonica A*, 116(4), 661-663.

*Physica*, 58-207.

1107-1111.

8071-807111.

(accessed 5 June 2012)., 8.

10.1088/00318949 /2012/T149/014025.

*SPIE*, 8439, 84391M.

One of the problems in high speed computing is the limited capabilities of communication links in digital high performance electronic systems. Too slow and too few interconnects be‐ tween VLSI circuits cause a bottleneck in the communication between processor and memo‐ ry or, especially in multiprocessor systems, among the processors. Moreover, the problem is getting worse since the increasing integration density of devices like transistors leads to a higher requirement in the number of necessary channels for the off-chip communication. Hence, we are currently in a situation, which is characterized by too few off-chip links and too slow long on-chip lines, what is described as the interconnect crisis in VLSI technology [1]. More than ten years the use of optical interconnects is discussed as an alternative to solve the mentioned problems on interconnect in VLSI technology [2]. A lot of prototypes and demonstrator systems were built to prove the use of optics or optoelectronics for offchip and on-chip interconnects [3]. The possibilities of current VLSI technology would allow integrating a massively-parallel array processor consisting of a few hundred thousand sim‐ ple processor elements (PEs) on a chip. Unfortunately it would be a huge problem to ar‐ range several of such PE arrays one after the other in order to realize a highly–parallel superscalar and super-pipelined architecture as well as an efficient coupling to a memory chip. The reason for these difficulties is the not sufficient number of external interconnects to move high data volumes from and to the circuits. In optoelectronic VLSI one tries to solve limitation problem by realizing external interconnects not at the edge of a chip but with ar‐

© 2013 Krasilenko et al.; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 Krasilenko et al.; licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

rays of optical detectors and light emitters which send and receive data directly out from the chip area. Honeywell has developed such devices with VCSEL diodes (vertical surface emit‐ ting laser diodes) and metal – semiconductor – metal photo-detectors in research project [4].

Taking into consideration the above-described approach, consisting in universality, let us recollect some known facts regarding the number of functions. The number of Boolean func‐ tions of *n* variables in algebra of two-valued logic (TVL), which is also Boolean algebra,

Design and Modeling of Optoelectronic Photocurrent Reconfigurable (OPR) Multifunctional Logic Devices (MFLD) as

*k*–valued logic (*k*>2) are reflections*An* → *A*, where *A*={0, 1,... *k*-1}, and the number of func‐

∧

CL algebra can be infinite or finite (the set of reflections is always infinite). CL functions are called only those functions of the set*N*∧, which are realized by formulas. The number *N*∧ of CL functions in the most developed CL algebra – quasi-Boolean Cleenee algebra (*Δ* =(*Cu*,∧,∨,-)), in which any function on any set of arguments takes the value of one of the arguments or its negation, is finite. In this case the number *N*∧(*n*) of functions of *n* argu‐ ments increases with increase of *n* very rapidly [4]:*N*∧(0)=2 ;*N*∧(1)=6;*N*∧(2)=84;*N*∧(3)=43918.

We would like to draw the attention to the fact, that both natural neurons and their more complex physical and mathematical models suggest discrete-analog and purely analog means for information processing with different level of accuracy, with the possibility of re‐ arrangement of chosen coding system. This, in its turn, requires corresponding image neu‐ ron circuit engineering with programmable logic operations, with transition from analog to

Thus, the search of means aimed at construction of elements, especially universal (at least quasi-universal or multifunctional) with programmable tuning, able to perform not only op‐ erations of two-valued logic, but other matrix (multi-valued, continuous, neural-fuzzy, etc.) logic operations is very actual problem [15]. One of promising directions of research in this sphere is the application of time-pulse-coded architectures (TPCA) that were considered in works [18-20]. These architectures were generalized in [11], taking into account basic possi‐ ble approaches as well as system and mathematical requirements. The time-pulse represen‐ tation of matrix continuous-logic variables by two-level optic signals not only permits to increase functional possibilities (up to universality), stability to noise, stability and decrease requirements regarding alignment and optical system, but also simplify control circuits and adjustment circuits to required function, operation, and keep untouched the whole meth‐ odological basis of such universal elements construction, irrespective of valuedness of a log‐

But there is another approach based on the use of universal logic elements with the structure of multiple-input multiple-output (MIMO) and time-pulse coding. We call such elements the elements of picture type (PT). At increase of number of input operands and valuedness of logic (up to continuous) the number of executable functions also increases by the expo‐ nential law. This property allows simplifying operation algorithms of such universal optoe‐ lectronic logical elements and hence to raise information processing speed. Most general conceptual approaches to construction of universal picture neural elements and their mathe‐ matical rationales were presented in paper [11]. But those were only system and structural

. Algebra, formed by set *C*

logic (CL) algebra, and the number of CL functions, as reflections *Cu*

. In this TVL there are *N*2 =2*n* atoms, which are minterms. Functions of *n* variables

*u* = 0, 1 or *C*

∧ *b*

the Universal Circuitry Basis for Advanced Parallel High-Performance Processing

= −1, 1 is called continuous

http://dx.doi.org/10.5772/54540

351

*n* →*Cu* depending on the

equals22*n*

tions equals*Nk* =*k k n*

discrete processing, to storing etc.

ic and type of a logic.

This allows the realization of stacked 3-D chip architecture in principle. The main problems are not the manufacturing and operating of single devices but the combination of different passive optical elements with active optoelectronic and electronic circuits in one system. This requires sophisticated mounting and alignment techniques which allow low mechani‐ cal tolerances and the handling of thermal problems. At present the situation for smart de‐ tector circuits is much easier. They can be regarded as a subset of OE-VLSI circuits because they consist only of arrays of photo-detectors with corresponding evaluation circuit for ana‐ logue to digital converting. Optical detectors based on PN or PIN photodiodes can be mono‐ lithically integrated with digital electronics in silicon what simplifies the design enormously compared with OE-VLSI circuits that in addition contain sender devices realized in GaAs technologies. Furthermore smart detector circuits can be manufactured in nearly every semi‐ conductor fabric. Smart detectors or smart optical sensors show a great application field and market potential. Therefore our approach favors a smart pixel like architecture combining parallel signal detection with parallel signal processing in one circuit. Each pixel has its own PE what guarantees the fastest processing.

The strategic direction of solution of various scientific problems, including the problem of creation of artificial intelligence (AI) systems, human brain simulators, robotics systems, monitoring and control systems, decision-making systems, as well as systems based on arti‐ ficial neural networks, etc., becomes fast-acting and parallel processing of large2-D arrays of data (up to 1024x1024 and higher) using non-conventional computational systems, corre‐ sponding matrix logics (multi-valued, signed-digit, fuzzy logics, continuous, neural-fuzzy and others) and corresponding mathematical apparatus [5-11]. For numerous perspective re‐ alizations of optical learning neural networks (NN) with two dimensional structure [5], of recurrent optical NN [6], of the continuous logic equivalency models (CLEM) NN [7-10], the elements of matrix logic are required, and not only of two-valued property, threshold, hy‐ brid but also continuous, neural-fuzzy logics and adequate structure of vector-matrix com‐ putational procedures with basic operations of above-mentioned logics. Optic and optoelectronic technologies, methods and principles as well as corresponding element base provide attractive alternative for 2D data processing. These technologies and methods suc‐ cessfully decide problems of parallelism, input-output and interconnections. Advanced nontraditional parallel computing structures and systems, including neural networks, require both parallel processing and parallel information input/output. At the same time there are many new approaches that are based on new logics (neural-fuzzy, multi-valued, continuous etc.). The using of the standard sequential algorithms based on a few operations makes the approaches long-running. But only a few of them [12] can be used for processing of 2D data and perform wide range of needed arithmetic and logic operations). Generalization of scalar two-valued logic on matrix case has led to intensive development of binary images algebra (BIA) [13] and 2D Boolean elements for optic and optoelectronic processors [12-17].

Design and Modeling of Optoelectronic Photocurrent Reconfigurable (OPR) Multifunctional Logic Devices (MFLD) as the Universal Circuitry Basis for Advanced Parallel High-Performance Processing http://dx.doi.org/10.5772/54540 351

rays of optical detectors and light emitters which send and receive data directly out from the chip area. Honeywell has developed such devices with VCSEL diodes (vertical surface emit‐ ting laser diodes) and metal – semiconductor – metal photo-detectors in research project [4].

This allows the realization of stacked 3-D chip architecture in principle. The main problems are not the manufacturing and operating of single devices but the combination of different passive optical elements with active optoelectronic and electronic circuits in one system. This requires sophisticated mounting and alignment techniques which allow low mechani‐ cal tolerances and the handling of thermal problems. At present the situation for smart de‐ tector circuits is much easier. They can be regarded as a subset of OE-VLSI circuits because they consist only of arrays of photo-detectors with corresponding evaluation circuit for ana‐ logue to digital converting. Optical detectors based on PN or PIN photodiodes can be mono‐ lithically integrated with digital electronics in silicon what simplifies the design enormously compared with OE-VLSI circuits that in addition contain sender devices realized in GaAs technologies. Furthermore smart detector circuits can be manufactured in nearly every semi‐ conductor fabric. Smart detectors or smart optical sensors show a great application field and market potential. Therefore our approach favors a smart pixel like architecture combining parallel signal detection with parallel signal processing in one circuit. Each pixel has its own

The strategic direction of solution of various scientific problems, including the problem of creation of artificial intelligence (AI) systems, human brain simulators, robotics systems, monitoring and control systems, decision-making systems, as well as systems based on arti‐ ficial neural networks, etc., becomes fast-acting and parallel processing of large2-D arrays of data (up to 1024x1024 and higher) using non-conventional computational systems, corre‐ sponding matrix logics (multi-valued, signed-digit, fuzzy logics, continuous, neural-fuzzy and others) and corresponding mathematical apparatus [5-11]. For numerous perspective re‐ alizations of optical learning neural networks (NN) with two dimensional structure [5], of recurrent optical NN [6], of the continuous logic equivalency models (CLEM) NN [7-10], the elements of matrix logic are required, and not only of two-valued property, threshold, hy‐ brid but also continuous, neural-fuzzy logics and adequate structure of vector-matrix com‐ putational procedures with basic operations of above-mentioned logics. Optic and optoelectronic technologies, methods and principles as well as corresponding element base provide attractive alternative for 2D data processing. These technologies and methods suc‐ cessfully decide problems of parallelism, input-output and interconnections. Advanced nontraditional parallel computing structures and systems, including neural networks, require both parallel processing and parallel information input/output. At the same time there are many new approaches that are based on new logics (neural-fuzzy, multi-valued, continuous etc.). The using of the standard sequential algorithms based on a few operations makes the approaches long-running. But only a few of them [12] can be used for processing of 2D data and perform wide range of needed arithmetic and logic operations). Generalization of scalar two-valued logic on matrix case has led to intensive development of binary images algebra

(BIA) [13] and 2D Boolean elements for optic and optoelectronic processors [12-17].

PE what guarantees the fastest processing.

350 Optoelectronics - Advanced Materials and Devices

Taking into consideration the above-described approach, consisting in universality, let us recollect some known facts regarding the number of functions. The number of Boolean func‐ tions of *n* variables in algebra of two-valued logic (TVL), which is also Boolean algebra, equals22*n* . In this TVL there are *N*2 =2*n* atoms, which are minterms. Functions of *n* variables *k*–valued logic (*k*>2) are reflections*An* → *A*, where *A*={0, 1,... *k*-1}, and the number of func‐ tions equals*Nk* =*k k n* . Algebra, formed by set *C* ∧ *u* = 0, 1 or *C* ∧ *b* = −1, 1 is called continuous logic (CL) algebra, and the number of CL functions, as reflections *Cu n* →*Cu* depending on the CL algebra can be infinite or finite (the set of reflections is always infinite). CL functions are called only those functions of the set*N*∧, which are realized by formulas. The number *N*∧ of CL functions in the most developed CL algebra – quasi-Boolean Cleenee algebra (*Δ* =(*Cu*,∧,∨,-)), in which any function on any set of arguments takes the value of one of the arguments or its negation, is finite. In this case the number *N*∧(*n*) of functions of *n* argu‐ ments increases with increase of *n* very rapidly [4]:*N*∧(0)=2 ;*N*∧(1)=6;*N*∧(2)=84;*N*∧(3)=43918.

We would like to draw the attention to the fact, that both natural neurons and their more complex physical and mathematical models suggest discrete-analog and purely analog means for information processing with different level of accuracy, with the possibility of re‐ arrangement of chosen coding system. This, in its turn, requires corresponding image neu‐ ron circuit engineering with programmable logic operations, with transition from analog to discrete processing, to storing etc.

Thus, the search of means aimed at construction of elements, especially universal (at least quasi-universal or multifunctional) with programmable tuning, able to perform not only op‐ erations of two-valued logic, but other matrix (multi-valued, continuous, neural-fuzzy, etc.) logic operations is very actual problem [15]. One of promising directions of research in this sphere is the application of time-pulse-coded architectures (TPCA) that were considered in works [18-20]. These architectures were generalized in [11], taking into account basic possi‐ ble approaches as well as system and mathematical requirements. The time-pulse represen‐ tation of matrix continuous-logic variables by two-level optic signals not only permits to increase functional possibilities (up to universality), stability to noise, stability and decrease requirements regarding alignment and optical system, but also simplify control circuits and adjustment circuits to required function, operation, and keep untouched the whole meth‐ odological basis of such universal elements construction, irrespective of valuedness of a log‐ ic and type of a logic.

But there is another approach based on the use of universal logic elements with the structure of multiple-input multiple-output (MIMO) and time-pulse coding. We call such elements the elements of picture type (PT). At increase of number of input operands and valuedness of logic (up to continuous) the number of executable functions also increases by the expo‐ nential law. This property allows simplifying operation algorithms of such universal optoe‐ lectronic logical elements and hence to raise information processing speed. Most general conceptual approaches to construction of universal picture neural elements and their mathe‐ matical rationales were presented in paper [11]. But those were only system and structural solutions that is why they require further development and perfection. Mathematical and other theoretical fundamentals of design of matrix multi-functional logical devices with fast acting programmable tuning were considered in paper[19], where expediency of functional basis unification, that is promising for optoelectronic parallel-pipeline systems (OEPS) with command-flow 2D-page (picture) organization [20], necessity in arrays of optic or optoelec‐ tronic triggers (memory elements) of picture type for storage of information and controlling adjusting operands as well as perspective principles of presentation and coding of multi-val‐ ued matrix data (spatial, time-pulse and spectral) were shown. Besides, the analysis of vari‐ ous algebra logics [11, 19, 21-24] for functional systems of switching functions, in spite of their diversity allows us to suggest a very useful idea, in our opinion, that lies in following.

form contrast-conversion (complementary operand) image for analog picture optic inputs if

Design and Modeling of Optoelectronic Photocurrent Reconfigurable (OPR) Multifunctional Logic Devices (MFLD) as

the Universal Circuitry Basis for Advanced Parallel High-Performance Processing

http://dx.doi.org/10.5772/54540

353

Thus, becomes obvious that for time – pulse coding realization of PNE of matrix-continuous -logic (MCL) with programmable tuning is necessary UPE of TVL or picture MFLD, by means of which continuously – logic operations over time – pulse signals can be realized. In Figure 1 selection of picture logic functions is carried out by electric adjusting signals and all array cells will realize the same function at the same time. For many appendices it is expedi‐ ent to choose a logic function at each point of the matrix processor, and therefore there is a desire to make management and tuning also in the form of optical matrix operands. It essen‐ tially expands functionality of such processors and MFLD on which basis they are realized.

In work [25] MFLD of two-valued logic (TVL) on current mirrors, photodiodes and LEDs with schemes of their drivers are described and simulated. They are relatively difficult as contain four current mirrors (CM), four schemes ХОR, four elements АND and one logic ele‐ ment OR. In the same work different optoelectronic circuitry were offered on base of 2-4 CM and one photo diode, realizing the Boolean operations AND, NOT, OR, NOR, et al with po‐ tential and current outputs. They are based on threshold elements, comparators of currents (photocurrents) on current mirrors and circuitry of limited subtraction (CLS). Such base ele‐ ments also were used for realization of other elements of continuous logic, including opera‐ tions equivalence (nonequivalence) and etc. [21, 26, 27]. Therefore developing further this

PWMs PT have complementary outputs.

**Figure 1.** The PNE of matrix-continuous-logic (MCL) with programmable tuning

approach we use for design of the OPR MFLD.

It is possible to create more sophisticated problem-oriented processors, in which the specific time-pulse operands encoding and only elements of two-valued logic are used, which will realize functions of different logics, continuous etc. Taking into account the universality, parallel information processing of the universal elements and the use of only two-valued logic elements for implementation of all other operations the approach is a very promising.

That is why the aim of the given work is to consider the results of design and investigation of optoelectronic smart time-pulse coded photocurrent reconfigurable MFLD as basic com‐ ponents for 2D-array logic devices for advanced neural networks and optical computers.