An event analyzer includes an event log collection module configured to collect an event log, an event log storage module configured to convert the event log into an event matrix and to store the event matrix, an event occurrence-order determination module configured to determine occurrence-order of device events based on the event matrix, a Bayesian network generation module configured to specify device events serving as parent node candidates, to calculate evaluation values corresponding to each specified parent node candidate at a virtual device event obtained by shifting the device event serving as a processing object each unit time, and to select an device event serving as a parent node together with a shift amount, and an analysis module configured to output an device event estimated as a cause of an device event to be analyzed, or an device event estimated to occur later based on the shift amount.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. An event analyzer configured to analyze events including alarms which occur in a plurality of devices, and operations which are performed on the plurality of devices, the event analyzer, comprising: an event log collection module configured to collect an event log including occurrence-time-and-date of the event, a device identifier, and an event-type identifier; an event log storage module configured to convert the event log into an event matrix that represents, in chronological order, presence/absence of occurrence of each device event obtained by combining the device identifier with the event type identifier with each other, and to store the event matrix; an event occurrence-order determination module configured to determine occurrence-order of device events, based on the event matrix; a Bayesian network generation module configured to specify device events serving as parent node candidates with respect to a device event serving as a processing object, based on the occurrence-order, to calculate evaluation values corresponding to each specified parent node candidate, based on an information amount reference, at a virtual device event obtained by shifting the device event serving as a processing object each unit time, and to select an device event serving as a parent node together with a shift amount, thereby to generate a Bayesian network; and an analysis module configured to output a device event estimated as a cause of a device event to be analyzed, or a device event estimated to occur later, together with time-difference information based on the shift amount. 2. The event analyzer according to claim 1, wherein the event occurrence-order determination module divides the event matrix into time windows having a predetermined time width, and determines occurrence-order of entirety of the device events, based on occurrence-order of device events in each time window. 3. The event analyzer according to claim 2, wherein, in a case where another parent node is selected, from unselected parent node candidates, for the device event serving as a processing object for which parent nodes have been selected, the Bayesian network generation module calculates the evaluation values, based on the information amount reference, at the virtual-device event obtained by shifting selected parent nodes and the device event serving as a processing object as a set of nodes each unit time, in a state in which a relative-shift amount of each of the selected parent nodes to the device event serving as a processing object at the time of selecting the parent node is maintained. 4. The event analyzer according to claim 3, wherein a maximum value of the shift amount is equal to the time width of each time window. 5. A computer-readable storage medium, storing a program which allows a computer to function as an event analyzer configured to analyze events including alarms which occur in a plurality of devices, and operations performs on the plurality of devices, the event analyzer, comprising: an event log collection module configured to collect an event log including occurrence-time-and-date of the event, a device identifier, and an event-type identifier; an event log storage module configured to convert the event log into an event matrix that represents, in chronological order, presence/absence of occurrence of each device event obtained by combining the device identifier with the event type identifier with each other, and to store the event matrix; an event occurrence-order determination module configured to determine occurrence-order of device events, based on the event matrix; a Bayesian network generation module configured to specify device events serving as parent node candidates with respect to a device event serving as a processing object, based on the occurrence-order, to calculate evaluation values corresponding to each specified parent node candidate, based on an information amount reference, at a virtual device event obtained by shifting the device event serving as a processing object each unit time, and to select an device event serving as a parent node together with a shift amount, thereby to generate a Bayesian network; and an analysis module configured to output a device event estimated as a cause of a device event to be analyzed, or a device event estimated to occur later, together with time-difference information based on the shift amount.