Patent Publication Number: US-2023135438-A1

Title: Information processing system, information processing method, and non-transitorycomputer-readable recording medium

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority from Japanese Application JP2021-176910 filed on Oct. 28, 2021, the content to which is hereby incorporated by reference into this application. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to information processing systems, information processing methods, and non-transitory computer-readable recording mediums. 
     2. Description of the Related Art 
     Conventional techniques have been known that evaluate the influential power that an entity has on another entity through quantification using a shareholding ratio. Examples of an entity include countries, businesses, and people. 
     “Mizuno T, Doi S, Kurizaki S (2020) The power of corporate control in the global ownership network. PLoS ONE 15(8): e0237862. https://doi.org/10.1371/journal.pone.0237862” proposes a technique of quantifying the influential power by simply adding up shareholding ratios in cases where an entity has indirect influential power on another entity. Japanese Unexamined Patent Application Publication, Tokukai, No. 2021-005298 proposes another technique of quantifying the influential power between entities, by using the network power index (NPI). 
     For instance, if entities form an entity-connecting network that has a multilayer structure, it is difficult to properly evaluate the influential power by the technique of quantifying influential power between entities through simple addition of shareholding ratios. It is also difficult to properly evaluate the influential power by the technique of quantifying influential power between entities using the NPI. For instance, because the NPI employs a unique index, it is difficult to describe relevance between the NPI value and the influence level between entities if the NPI value is not 1. In addition, the NPI-based technique is not capable of analyzing the influence level of an entity that effectively controls another entity in the same entity network. 
     The present disclosure, in some aspects thereof, has an object to provide, for example, an information processing system, an information processing method, and a non-transitory computer-readable recording medium that are capable of properly evaluating influence levels between entities. 
     The present disclosure, in an aspect thereof, is directed to an information processing system including: an obtaining unit configured to obtain an entity network representing mutual capital investment relations and mutual capital contribution ratios among a plurality of nodes corresponding to a plurality of entities; and an analysis unit configured to analyze an influence level for each of a plurality of higher nodes to which a particular one of the plurality of nodes is directly or indirectly linked based on at least one of the capital contribution ratios that is assigned to a path along which one of the capital investment relations from the particular node is traced, by using the capital contribution ratio in the particular node as an index, wherein when the capital contribution ratio of one of two or more of the plurality of higher nodes to which an analysis target node that is a target in analyzing the influence level is linked is in excess of half, the analysis unit analyzes the one higher node the capital contribution ratio of which is in excess of half to be effectively controlling the analysis target node. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    shows an exemplary structure of a system including an information processing system. 
         FIG.  2    shows an exemplary structure of a server system. 
         FIG.  3    shows an exemplary structure of a terminal device. 
         FIG.  4    is a diagram of a business ownership stake network analysis. 
         FIG.  5 A  is a diagram illustrating an exemplary conventional NPI calculation. 
         FIG.  5 B  is a diagram illustrating another exemplary conventional NPI calculation. 
         FIG.  6 A  is a diagram illustrating an exemplary indirect shareholding ratio calculation. 
         FIG.  6 B  is a diagram illustrating another exemplary indirect shareholding ratio calculation. 
         FIG.  7    is a diagram illustrating an exemplary entity network. 
         FIG.  8    is a diagram illustrating an exemplary influence level calculation process using an indirect shareholding ratio. 
         FIG.  9    is a continuation (diagram) to  FIG.  8   . 
         FIG.  10    is a continuation (diagram) to  FIG.  9   . 
         FIG.  11    is a continuation (diagram) to  FIG.  10   . 
         FIG.  12    is a diagram illustrating an exemplary method of calculating an indirect shareholding ratio. 
         FIG.  13    is a flow chart representing an exemplary flow of an influence level calculation process using a bottom-up method. 
         FIG.  14    is a continuation (flow chart) to  FIG.  13   . 
         FIG.  15    is a diagram showing an exemplary presentation screen. 
         FIG.  16    is a diagram illustrating another exemplary entity network. 
         FIG.  17    is a diagram illustrating an exemplary node outputted by a top-down method. 
         FIG.  18    is a flow chart representing an exemplary flow of a top-down method. 
         FIG.  19 A  is a diagram illustrating an exemplary indirect shareholding ratio calculation in accordance with a variation example. 
         FIG.  19 B  is a diagram illustrating another exemplary indirect shareholding ratio calculation in accordance with a variation example. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following will describe the present embodiment with reference to drawings. Identical and equivalent elements in the drawings are denoted by the same reference numerals, and description thereof is not repeated. The scope of the present invention is not unreasonably limited by the present embodiment described below. Not all the members described in the present embodiment are essential to the present disclosure. 
     1. OSINT System 
     1.1 Example of System Structure 
       FIG.  1    shows an exemplary structure of a system including an information processing system  10  in accordance with the present embodiment. The system in accordance with the present embodiment includes a server system  100  and a terminal device  200 . The structure of the system including the information processing system  10  is not necessarily limited to the example shown in  FIG.  1    and may be modified in various manners, for example, by omitting some parts of the structure or by including an additional structure. For instance,  FIG.  1    shows two terminal devices  200 - 1  and  200 - 2  as the terminal device  200 . Alternatively, there may be provided only one terminal device  200  or three or more terminal devices  200 . The same description applies to  FIG.  2    and  FIG.  3    (detailed below) regarding variations including the omission of parts of the structure and the inclusion of an additional structure. 
     The information processing system  10  in accordance with the present embodiment is an equivalent of, for example, the server system  100 . The server system  100  is an equivalent of a computer. The technique in accordance with the present embodiment is however not necessarily limited to this example. The functions of the information processing system  10  may be provided by a distributed system that includes the server system  100  and other apparatus. For instance, the information processing system  10  in accordance with the present embodiment may be implemented by distributed processing between the server system  100  and the terminal device  200 . The following description will focus on examples where the information processing system  10  is the server system  100 . 
     The server system  100  may include a single server or a plurality of servers. For instance, the server system  100  may include a database server and an application server. The database server may contain entity networks (which will be described later) and other various data. The application server may perform variations processes in accordance with the present embodiment. The plurality of servers may be physical servers or virtual servers. When a virtual server is used, the virtual server may be provided either by a single physical server or by a plurality of physical servers in a distributed manner. The specific structure of the server system  100  can have many variations in the present embodiment as described here. 
     The terminal device  200  is used by a user of the information processing system  10 . The terminal device  200  may be a PC (personal computer), a mobile terminal such as a smartphone, or any other like apparatus. 
     The server system  100  is connected to the terminal device  200 - 1  and the terminal device  200 - 2 , for example, over a network. The terminal device  200 - 1  and the terminal device  200 - 2  will be simply referred to as the terminal device  200  throughout the following description when there is no need to distinguish between multiple terminal devices. The network in this context is, for example, a public communications network such as the Internet and may be, for example, a LAN (local area network). 
     The information processing system  10  in accordance with the present embodiment is an OSINT (open source intelligence) system, for example, for collecting and analyzing data related to a target by using, for example, open information. The open information in this context includes various information that is legally available and widely accessible, such as securities reports, inter-industry relations tables, governments&#39; official announcements, and news reports on countries and businesses. The information processing system  10  in accordance with the present embodiment is not necessarily limited to an OSINT system. 
     The server system  100  generates nodes with various attributes on the basis of open information. Each node represents a given entity and may in this context be a person, a business, or a country. Attributes are, for example, the information determined on the basis of open information and include information on the entity including information on shareholding ratios. The attributes may include the entity&#39;s nationality, business field, sales, number of employees, board members, traded goods, and various other information. 
     When a given node has an attribute associated with another node, the two nodes are linked together by a directional edge. As an example, when a given entity has a shareholder that is another entity, the two nodes representing the respective entities are linked together by an edge representing a shareholding ratio. An edge in this context has directionality from an entity that receives influence to an entity that gives influence. The edge has, for example, directionality from an entity that receives investment to an entity that makes the investment. 
     According to the technique in accordance with the present embodiment, the server system  100  obtains an entity network composed of a plurality of nodes, each representing an entity, that are linked by attribute-based directional edges. In other words, the entity network is a directed graph. The server system  100  performs analysis based on the entity network and implements a process of presenting results of the analysis. For instance, the terminal device  200  is used by a user of a service provided by an OSINT system. For instance, the user requests the server system  100  (information processing system  10 ) to perform some analysis by using the terminal device  200 . The server system  100  performs analysis based on the entity network and feeds the results of the analysis to the terminal device  200  as a response. 
       FIG.  2    is a detailed block diagram of an exemplary structure of the server system  100 . The server system  100  includes, for example, a processing unit  110 , a memory unit  120 , and a communications unit  130 . 
     The processing unit  110  in accordance with the present embodiment includes prescribed hardware. The hardware may include either one or both of a digital signal processing circuit and an analog signal processing circuit. For instance, the hardware may include one or more circuit elements or devices mounted on a circuit board. Each circuit device is, for example, an IC (integrated circuit) chip or an FPGA (field-programmable gate array). Each circuit element is, for example, a resistor or a capacitor. 
     The processing unit  110  may be provided by one or more processors. The server system  100  in accordance with the present embodiment includes, for example, an information-containing memory and a processor that operates on the basis of the information stored in the memory. The information is, for example, programs and various data. The processor includes hardware. The processor may be any processor including a CPU (central processing unit), a GPU (graphics processing unit), and a DSP (digital signal processor). The memory may be, for example, a semiconductor memory such as a SRAM (static random access memory), a DRAM (dynamic random access memory), or a flash memory; a register; a magnetic storage device such as a hard disk drive (HDD); or an optical storage device such as an optical disc drive. For instance, the memory contains computer-readable instructions, so that the processor can execute the instructions to provide the functions of the processing unit  110 . These instructions may be a set of instructions contained in a program or instructions for instructing the processor hardware circuit to operate. 
     The processing unit  110  in accordance with the example of  FIG.  2    includes, for example, an entity network obtaining unit  111 , an influence level calculation unit  112 , and a presentation processing unit  113 . 
     The entity network obtaining unit  111  obtains an entity network  121 . For instance, the entity network obtaining unit  111  may generate the entity network  121  on the basis of open information. The entity network obtaining unit  111  stores the generated entity network  121  in the memory unit  120 . The entity network obtaining unit  111 , upon performing a process in accordance with the present embodiment, obtains the entity network  121  stored in the memory unit  120 . 
     The entity network  121  may be generated by a system other than the information processing system  10  in accordance with the present embodiment. When this is the case, the entity network obtaining unit  111  may obtain an entity network from another system via the communications unit  130 . 
     The entity network obtaining unit  111  obtains, as the entity network  121 , for example, a network of entities interconnected by capital investment relations. The entity network  121  includes plurality of entities. Each entity corresponds to a node as described above. Nodes are connected by edges on the basis of capital investment relations. In addition, each edge is assigned a capital contribution ratio. The capital contribution ratio represents a shareholding ratio. Information on the shareholding ratio can also obtained on the basis of the open information described above. 
     The influence level calculation unit  112  implements an influence level calculation process of calculating the influence level of a given entity on another entity on the basis of the entity network  121 . The influence level calculation unit  112  is an equivalent of an analysis unit. 
     The presentation processing unit  113  performs a process of causing the terminal device  200  to display a presentation screen that presents, for example, the links between nodes in the entity network  121 , the capital contribution ratios assigned to the edges, and indirect shareholding ratios corresponding to the respective nodes. The presentation processing unit  113  is an equivalent of a display controlling unit. 
     The memory unit  120  is a working area for the processing unit  110  and contains various information. The memory unit  120  may be any memory device including a semiconductor memory such as an SRAM, a DRAM, a ROM, or a flash memory; a register; a magnetic storage device such as a hard disk drive; or an optical storage device such as an optical disc drive. 
     The memory unit  120  contains, for example, the entity network  121  obtained by the entity network obtaining unit  111 . The memory unit  120  may contain various information related to the processes in accordance with the present embodiment. 
     The communications unit  130  is an interface for performing communications over a network and includes, for example, an antenna, an RF (radio frequency) circuit, and a baseband circuit. The communications unit  130  may operate under the control of the processing unit  110  and may include a communications controlling processor other than the processing unit  110 . The communications unit  130  is an interface for performing communications in accordance with, for example, the TCP/IP (transmission control protocol/internet protocol). The specific communications scheme may have many variations. 
       FIG.  3    is a detailed block diagram of an exemplary structure of the terminal device  200 . The terminal device  200  includes a processing unit  210 , a memory unit  220 , a communications unit  230 , a display unit  240 , and an operation unit  250 . 
     The processing unit  210  includes hardware including either one or both of a digital signal processing circuit and an analog signal processing circuit. The processing unit  210  may be provided by a processor. This processor may be any processor including a CPU, a GPU, and a DSP. The processor executes the instructions stored in the memory of the terminal device  200  to provide the functions of the processing unit  210 . 
     The memory unit  220  is a working area for the processing unit  210  and provided by any memory such as an SRAM, a DRAM, or a ROM. 
     The communications unit  230  is an interface for performing communications over a network and includes, for example, an antenna, an RF circuit, and a baseband circuit. The communications unit  230  communicates with the server system  100  over, for example, a network. 
     The display unit  240  is an interface for displaying various information and may be a liquid crystal display device, an OLED display device, or a display device that operates under any other scheme. The display unit  240  displays, for example, a presentation screen (detailed later) under the control of a presentation processing unit  1113  of the server system  100 . 
     The operation unit  250  may be, for example, a button on the terminal device  200 . The display unit  240  and the operation unit  250  may be combined to form a touch panel. 
     1.2 Specific Examples of Service 
     A description will be given next of specific examples of the service provided by the information processing system  10  (OSINT system). Business ownership stake network analysis is taken below as an example of specific services. 
       FIG.  4    is a diagram of business ownership stake network analysis and shows an exemplary entity network representing capital investment relations. A network is formed that represents capital investment relations between, for example, countries and businesses on the basis of the information representative of the shareholders and their capital contribution ratios found in open information as shown in  FIG.  4   . 
     The influence level calculation unit  112  may analyze, for example, the influence level that various countries and businesses have on another business. The influence level in this context indicates controlling power exercised through investment. Specific examples of the influence level calculation process will be detailed later. 
     For instance, it is possible to approximately learn what controlling power a particular country has on the supply of products in a given industry sector, by finding the influence level that the country has on businesses in that industry sector. It is, for example, possible to evaluate the influence of a critical domestic incident on the stable supply of a product. The influence level calculation unit  112  may find the influential power that individual countries have on global businesses. In this manner, it is possible to learn power balance between countries. It is also possible to learn about how the power balance is changing, by finding temporal changes of the influential power that individual countries have on global businesses. 
     Alternatively, the influence level calculation unit  112  may find the influential power that a country has on a business related to infrastructure in a given country. The infrastructure-related business may be a business related to electric power or another form of energy or a business that provides a mobile communications network. In this manner, it becomes possible to evaluate the risk of the infrastructure stopping functioning. The influence level calculation unit  112  may alternatively find the influential power on a business that owns technology that can be diverted to military use. In this manner, it becomes possible to detect security risk. 
     The influence level calculation unit  112  may find changes that may occur in the influence level of a country or business when they take a particular course of action. As an example, in the wake of a shift in the foreign policy of a given country, it is possible to simulate the influence of the new foreign policy on other countries, by calculating the influence level before and after the shift. 
     By using the influence level calculation unit  112 , it also becomes possible to analyze complex capital investment relations, which humans would find hard to detect, through business ownership stake network analysis. 
     Countries, businesses, and important people have formed networks that are ever more global and complex than humans can analyze manually. In contrast, the OSINT system described above is capable of the analysis of, for example, networks representing business controls through investment. Since the OSINT system is capable of deciphering complex relationships, the government and businesses can, for example, devise an optimal strategy. 
     2. Details of Processes 
     The following will describe processes in detail in accordance with the present embodiment. A technique in accordance with the present embodiment refers to business ownership stake network analysis in the narrow sense of the term and is a technique that is applicable to any technique other than business ownership stake network analysis. 
     2.1 Basics of Calculation of Influence Level 
     A description is given of a technique of calculating an inter-nodal influence level.  FIG.  5 A  is a diagram illustrating an exemplary conventional NPI calculation.  FIG.  5 B  is a diagram illustrating another exemplary conventional NPI calculation. In the example of  FIG.  5 A , entity B, entity C, and entity D own the shares of entity A. The shareholding ratios of entity B and entity C are 30%, and the shareholding ratio of entity D is 40%. In addition, entity B and entity E own the shares of entity C. The shareholding ratios of entity B and entity E are 50% respectively. 
     Since NPI-determining techniques are conventional art, detailed description thereof is omitted. The NPI of shareholder i in business j is given by formula (1) below. 
     
       
         
           
             
               
                 
                   Math 
                   . 
                       
                   1 
                 
               
               
                  
               
             
             
               
                 
                   
                     NPI 
                     = 
                     
                       
                         ∑ 
                         cj 
                       
                       
                         
                           pj 
                           ⁡ 
                           ( 
                           
                             i 
                             ⁢ 
                             
                               
                                 ❘ 
                                 &#34;\[LeftBracketingBar]&#34; 
                               
                               Cj 
                             
                           
                           ) 
                         
                         ⁢ 
                         
                           p 
                           ⁡ 
                           ( 
                           Cj 
                           ) 
                         
                       
                     
                   
                   , 
                 
               
               
                 
                   ( 
                   1 
                   ) 
                 
               
             
           
         
       
     
     where pj(i|C j ) is the probability of shareholder i controlling business j. 
     Using this formula (1), the NPI of entity B in entity A in  FIG.  5 A  is calculated to be ⅔. 
     Meanwhile, in  FIG.  5 B , the shareholding ratio of entity B in entity C is 51%, and the shareholding ratio of entity E in entity C is 49%. In this case, the NPI of entity B in entity A is calculated to be 1 because entity B has influential power over entity A via entity C. 
     When the NPI is 1 as in  FIG.  5 B , it is understand that entity B effectively controls entity A. Meanwhile, when the NPI is ⅔ as in  FIG.  5 A , it is difficult to describe in specific terms how much influential power this NPI value represents. 
       FIG.  6 A  is a diagram illustrating an exemplary indirect shareholding ratio calculation in accordance with the present embodiment.  FIG.  6 B  is a diagram illustrating another exemplary indirect shareholding ratio calculation in accordance with the present embodiment. An indirect shareholding ratio is given by ISH (indirect shareholding) and is a value that indicates a direct or indirect influence level of an entity on another, particular entity in terms of a shareholding ratio. In the examples in  FIGS.  6 A and  6 B , the particular entity is entity A. For instance, entity A is a particular business (company). 
     In the entity network in accordance with the present embodiment, unlike the NPI, entities are linked by directional edges from an entity that receives influence to an entity that gives influence. Entity A in the example in  FIG.  6 A  has its shares owned by entities B, C, and D. The shareholding ratio of entity B in entity A is 30%. The shareholding ratio of entity C in entity A is 30%. The shareholding ratio of entity D in entity A is 40%. 
     Entity C has its shares owned by entity B and entity E. The shareholding ratio of entity B in entity C is 50%. The shareholding ratio of entity E in entity C is also 50%. 
     Therefore, entity B has direct influential power over entity A and additionally has indirect influential power over entity A via entity C. The indirect shareholding ratio ISH of entity B in entity A is hence equal to 45% (=30%+0.5×30%). 
     The example in  FIG.  6 B  differs from the example in  FIG.  6 A  in that the shareholding ratio of entity B in entity C is 51% and that the shareholding ratio of entity E in entity C is 49%. 
     In the example in  FIG.  6 B , entity C has its shares owned by entity B and entity E, and the shareholding ratio of entity B is 51%, which is in excess of 50%. An entity (e.g., business) that has a shareholding ratio in excess of 50% generally has the sole power to pass ordinary resolutions and can be the controlling shareholder. It is therefore analyzed that entity B effectively controls entity C. 
     In other words, the indirect shareholding ratio ISH of entity B in entity A can be regarded as being equal to 60% (=30%+1×30%) at maximum. Strictly, if the shareholding ratio of entity B in entity C is in excess of ⅔, there is no problem for entity B completely controls entity C. However, since 51% is not in excess of ⅔, the 30% that is the shareholding ratio of entity C is not completely at entity B&#39;s own will. Therefore, a variation example is also possible where entity B effectively controls only 51% of entity A, and the effective controlling power of entity E over entity A is calculated to be 9%, which is what remains after the subtraction of entity D&#39;s 40% and entity B&#39;s 51%. However, the indirect shareholding ratio ISH of entity B in entity A here is assumed to be 60% at maximum in the following discussion because it is often preferable to overestimate the threat of the influential power of entity B over entity A. This variation example will be described later in detail. 
     In the example in  FIG.  5 A , the NPI of entity B in entity A is ⅔. However, when the NPI is ⅔, it is difficult to describe what the influence level of entity B on entity A signifies. 
     Meanwhile, in the example in  FIG.  6 A , the indirect shareholding ratio ISH of entity B in entity A is 45%. An indirect shareholding ratio ISH is a value that represents an influence level that takes into account an indirect influence level denoted using a shareholding ratio as an index. In other words, entity B can be analyzed to have, on entity A, a direct or indirect influence level denoted using a shareholding ratio of 45% as an index. For instance, the users and clients of the OSINT system would find it difficult to intuitively appreciate what influence level an NPI value represents. On the other hand, the users and clients would find it easy to intuitively appreciate the influence level denoted by a shareholding ratio. Since the indirect shareholding ratio in accordance with the present embodiment is denoted by an influence level on the basis of a shareholding ratio, it is possible to present the influence level in an easy-to-appreciate form to the users and clients. 
       FIGS.  6 A and  6 B  show examples of entity networks of a small number of entities. It is difficult to properly describe the influence level of an entity on another, particular entity even by an NPI-based technique, particularly, in a multilayered entity network of a large number of entities. 
     In contrast, by using the indirect shareholding ratio in accordance with the present embodiment, one can properly analyze, and present to users and clients in an easy-to-appreciate form, the influence level of an entity on another, particular entity even in a multilayered entity network of a large number of entities. Additionally, for a particular entity in a multilayered entity network, there may exist an entity substantially controlling the particular entity (substantially controlling entity) in addition to an ultimate controlling entity. It is difficult to analyze the influence level of a substantially controlling entity (e.g., a direct shareholder) by NPI techniques. In contrast, the technique in accordance with the present embodiment where the indirect shareholding ratio is used is capable of analyzing a substantially controlling entity. 
     2.2 Specific Example of Calculation of Indirect Shareholding Ratio 
     Example of Entity Network 
       FIG.  7    is a diagram illustrating an exemplary entity network. The exemplary entity network in  FIG.  7    includes nodes  1  to  13  each representing an entity. Two of these nodes are linked together by an edge on the basis of the mutual capital investment relation. The direction of the edge is from the entity that receives investment to the entity that makes the investment. 
     Additionally, each edge is assigned information on a shareholding ratio (capital contribution ratio). The information on each node, the information on each edge, and the information on each shareholding ratio can be obtained on the basis of, for example, the above-described open information. The entity network described here is obtained as the entity network  121  shown in  FIG.  2   . 
     In the technique of calculating an influence level by using an indirect shareholding ratio in accordance with the present embodiment, the influence level calculation unit  112  performs a process for calculating an influence level from a bottom node toward a higher node, where the bottom node is a particular node on which the influence level analysis is to be done. The bottom node corresponds to the particular node. The technique of calculating an influence level by using an indirect shareholding ratio is alternatively referred to as the bottom-up method. 
     Exemplary Influence Level Calculation Process Using Bottom-up Method 
       FIGS.  8  to  11    are diagrams illustrating exemplary influence level calculation processes using an indirect shareholding ratio. The following will describe examples where the entity network in  FIG.  7    is used. 
     The influence level calculation unit  112 , first, initializes a stack S and a path set P, which renders the stack S and the path set P empty sets. 
     In the following description, of the nodes in the entity network, the one of nodes  2  to  13  that is being processed other than node  1  (bottom node) will be referred to as the processed node. The processed node is a node linked directly or indirectly to the bottom node. The processed node corresponds to the analysis target node. 
     The stack S stores path information (weighted path) including information on the shareholding ratio assigned to the path running from node  1  (bottom node) to the processed node. The stack S is used to store a set of weighted paths. 
     When node  1  is linked indirectly to the processed node, there is a plurality of edges between node  1  and the processed node. In addition, when node  1  is linked directly to the processed node, there is a single edge between node  1  and the processed node. The one or more edges between node  1  and the processed node are referred to as paths in the present embodiment. Therefore, a path may include a single edge or a plurality of edges. 
     The path set P is used to store a set of weighted paths popped from the stack S. The influence level calculation unit  112  calculates an indirect shareholding ratio ISH using the set of weighted paths stored in the path set P. The stack S and the path set P are provided using, for example, a part of the memory area of the memory unit  120 . 
     The influence level calculation unit  112  obtains node  1 , which is a bottom node (particular node), from an entity network. The influence level calculation unit  112  then stores, in the stack S, a weighted path for each of nodes  2 ,  3 , and  4  linked to node  1 . 
     In the example of  FIG.  8   , the influence level calculation unit  112  stores, in the stack S, a weighted path for which the edge of the weighted path of the path from node  1  toward node  2  is assigned information (“0.3”) on the shareholding ratio. The influence level calculation unit  112  performs the same process on the weighted path of the path from node  1  toward node  3  and on the weighted path of the path from node  1  toward node  4  and stores the resultant weighted paths in the stack S.  FIG.  8    illustrates an example where the shareholding ratios are given in decimal numbers. Alternatively, the shareholding ratios may be given in percentage. 
     When the higher nodes for the bottom node or the processed node include a node with a shareholding ratio in excess of 50%, the influence level calculation unit  112  excludes the higher nodes other than this higher node from the processing target related to the processed node. For instance, when the plurality of higher nodes to which the processed node is directly linked includes a higher node that has a shareholding ratio in excess of 50% in the processed node, the influence level calculation unit  112  analyzes this higher node to be effectively controlling the processed node. 
     In such cases, the influence level calculation unit  112  rewrites the shareholding ratio of, among the plurality of higher nodes, the higher node that has a shareholding ratio in excess of 50% to 1, which is a maximum shareholding ratio. Additionally, the influence level calculation unit  112  excludes the one or more higher nodes other than that higher node from the processing target related to the processed node. The influence level calculation unit  112  performs the same process on the bottom node. 
     In the example of  FIG.  7   , nodes  2 ,  3 , and  4  each have a shareholding ratio of less than 50% in node  1 . Thus, the influence level calculation unit  112  stores node information on each node in the stack S. The stack S stores the three weighted paths shown in F 1  in  FIG.  8   . 
     The influence level calculation unit  112  retrieves the top weighted path (weighted path from node  1  toward node  2 ) from the three weighted paths stored in the stack S. The influence level calculation unit  112  obtains three higher nodes (nodes  5 ,  6 , and  7 ) for node  2  (processed node) from the entity network. 
     None of nodes  5 ,  6 , and  7  has a shareholding ratio in excess of 50% in node  2 . The influence level calculation unit  112  adds each of nodes  5 ,  6 , and  7  to the weighted path running from node  1  to node  2 . The influence level calculation unit  112  assigns information on the shareholding ratio corresponding to each of the edges that link node  2  to nodes  5 ,  6 , and  7 . 
     The influence level calculation unit  112  stores the weighted path running from node  1  to node  5 , the weighted path running from node  1  to node  6 , and the weighted path running from node  1  to node  7  in the stack S as shown in F 2  in  FIG.  8   . No changes are made to the weighted path running from node  1  to node  3  and the weighted path running from node  1  to node  4  both stored in the stack S. 
     The influence level calculation unit  112  retrieves the weighted path running from node  1  to node  5  stored on the top of the stack S. When the one or more higher nodes to which the processed node is linked includes a higher node that has a shareholding ratio in excess of 50%, the influence level calculation unit  112  rewrites the shareholding ratio of this higher node to 1. Additionally, the influence level calculation unit  112  excludes the higher nodes other than that higher node from the processing target related to node  1 . 
     As shown in the example in  FIG.  7   , node  5  has only one higher node, that is, node  10  with a shareholding ratio of 100%. In such cases, the influence level calculation unit  112  analyzes node  10  to be the node effectively controlling node  5  and assigns the shareholding ratio of 1 to the edge running from node  5  to node  10 . The influence level calculation unit  112  then stores the weighted path of the path running from node  1  to node  10  via nodes  2  and  5  in the path set P. The resultant stack S and path set P are shown in F 3  in  FIG.  8   . 
     The influence level calculation unit  112  retrieves the weighted path running from node  1  to node  6  stored on the top of the stack S. In the example of  FIG.  7   , similarly to node  5 , node  6  is effectively controlled by node  10 . The influence level calculation unit  112  stores the weighted path of the path running from node  1  to node  10  via nodes  2  and  6  in the path set P. The resultant stack S and path set P are shown in F 4  in  FIG.  8   . 
     The influence level calculation unit  112  retrieves the weighted path running from node  1  to node  7  stored on the top of the stack S. As shown in the example in  FIG.  7   , node  7  is linked to nodes  11 ,  12 , and  13  by respective edges. Of these three higher nodes (nodes  11 ,  12 , and  13 ), node  11  has a shareholding ratio of in excess of 50% in node  7 . 
     The influence level calculation unit  112  adds node  11  to the retrieved weighted path and rewrites the shareholding ratio for the edge linking node  7  to node  11  to 1. The influence level calculation unit  112  then stores the weighted path of the path running from node  1  to node  11  via node  2  and node  7  in the path set P. Additionally, the influence level calculation unit  112  excludes node  12  and node  13  from the processing target related to node  7 . The resultant stack S and path set P are shown in F 5  in  FIG.  8   . 
       FIG.  9    is a continuation (diagram) to  FIG.  8   . The influence level calculation unit  112  retrieves the weighted path running from node  1  to node  3  stored on the top of the stack S. As shown in the example of  FIG.  7   , node  3  is linked to nodes  2 ,  7 , and  8 , and the shareholding ratio of node  2  in node  3  is in excess of 50%. 
     The influence level calculation unit  112  adds node  2  to node  3  and rewrites the shareholding ratio for the edge linking node  3  to node  2  to 1. The influence level calculation unit  112  then stores the weighted path of the path running from node  1  to node  2  via node  3  in the path set P. Additionally, the influence level calculation unit  112  excludes nodes  7  and  8  from the processing target related to node  3 . The resultant stack S and path set P are shown in F 6  in  FIG.  9   . 
     The influence level calculation unit  112  retrieves the weighted path running from node  1  to node  2  via node  3  stored on the top of the stack S. As shown in the example of  FIG.  7   , node  2  is linked to nodes  5 ,  6 , and  7 , and none of these nodes has a shareholding ratio of in excess of 50% in node  3 . 
     The influence level calculation unit  112  adds nodes  5 ,  6 , and  7  to the weighted path running from node  1  to node  2  via node  3 , assigns respective shareholding ratios, and stores in the stack S. The resultant stack S and path set P are shown in F 7  in  FIG.  9   . 
     The same process as the process described above is performed on nodes  5 ,  6 , and  7 . Thus, the weighted path of the path running from node  1  to node  5 , the weighted path of the path running from node  1  to node  6 , and the weighted path of the path running from node  1  to node  7 , all stored in the stack S, are stored in the path set P. The resultant stack S and path set P are shown in F 8  in  FIG.  9   . 
       FIG.  10    is a continuation (diagram) to  FIG.  9   . Although the weighted paths stored in the path set P are not shown in F 9  to F 12  in  FIG.  10   , each weighted path corresponding to F 8  shown in the example of  FIG.  9    is stored in the path set P. The influence level calculation unit  112  performs the same process as the process described above. The resultant stack S and path set P are shown in F 9  to F 11  in  FIG.  10   . 
       FIG.  11    is a continuation (diagram) to  FIG.  10   . Although the weighted paths stored in the path set P are not shown in F 13  to F 14  in  FIG.  11   , each weighted path corresponding to F 8  shown in the example of  FIG.  9    is stored in the path set P. In F 13  in  FIG.  11   , the influence level calculation unit  112  retrieves the weighted path of the path linking node  1  to node  9  via node  2  from the stack S. The influence level calculation unit  112  then stores this weighted path in the path set P. This renders the stack S empty. The influence level calculation unit  112  ends the influence level calculation process here. 
       FIG.  12    is a diagram illustrating an exemplary method of calculating an indirect shareholding ratio. The path set P contains nine weighted paths X 1  to X 9  as a result of the above-described process. The influence level calculation unit  112  calculates an indirect shareholding ratio ISH using each weighted path X 1  to X 9 . 
     A description is now given of an example where the indirect shareholding ratio, ISH(2,1), of node  2  in node  1  is calculated. Note that in the indirect shareholding ratio ISH(2,1), 2 represents node  2 , and 1 represents node  1 . The same convention is used throughout the following description. Node  1  is linked to node  2  by paths X 1  to X 3  and paths X 4  to X 6 . Paths X 1  to X 3  share the same route from node  1  to node  2 , and paths X 4  to X 6  share the same route from node  1  to node  2 . 
     Paths X 1  to X 3  link node  1  directly to node  2 . The shareholding ratio assigned to the edge linking node  1  to node  2  along this route is 0.3. 
     Meanwhile, paths X 4  to X 6  link node  1  indirectly to node  2  via node  3 . The shareholding ratio assigned to the edge linking node  1  to node  3  is 0.3, and the shareholding ratio assigned to the edge linking node  3  to node  2  is 1. The influence level calculation unit  112  multiplies the plurality of shareholding ratios assigned to the indirect paths. In this case, the result of the multiplication is 0.3 (=0.3×1). 
     The influence level calculation unit  112  adds 0.3, which is the shareholding ratio for the path related to X 4  to X 6 , to 0.3, which is the shareholding ratio for the path related to X 1  to X 3 . Hence, the influence level calculation unit  112  calculates the indirect shareholding ratio, ISH(2,1), of node  2  in node  1  to be equal to 0.6. 
     A description is given next of an example where the indirect shareholding ratio, ISH(3,1), of node  3  in node  1  is calculated. Of weighted paths X 1  to X 9  in the example of  FIG.  12   , only paths X 1  to X 3  link node  1  to node  2 . Therefore, the influence level calculation unit  112  calculates the indirect shareholding ratio, ISH(3,1), of node  3  in node  1  to be equal to 0.3. 
     The same description applies to the other nodes. The influence level calculation unit  112  thus calculates the indirect shareholding ratios ISH of all the nodes to which node  1  (bottom node) is directly or indirectly linked.  FIG.  12    shows the indirect shareholding ratios ISH of all the nodes. 
     Here, the influence level calculation unit  112  may detect a node that has an indirect shareholding ratio ISH in excess of a prescribed threshold value. The prescribed threshold value may be set to any value. For instance, when the prescribed threshold value is set to 0.5, the influence level calculation unit  112  detects nodes  2  and  10 . 
     On the basis of the entity network in the example of  FIG.  7   , detected node  10  can be determined to have ultimate controlling power. Additionally, detected node  2  indicates the highest indirect shareholding ratio of all the nodes. It is therefore determined that detected node  2  has effective controlling power over node  1 . 
       FIG.  13    is a flow chart representing an exemplary flow of an influence level calculation process using a bottom-up method. The influence level calculation unit  112  initializes the path set P and the stack S (step S 101 ). The influence level calculation unit  112  obtains each higher node to which the bottom node is linked and the shareholding ratio assigned to each path (step S 102 ). Letting n 1  denote the bottom node, each higher node and each shareholding ratio are given by (2) below. Note that “n” represents the node represents, and the “q” represents shareholding ratio. 
       Math. 2 
       Higher Nodes:  n   1,   1   n   1,   2    . . . n   1,   N(1) , Shareholding Ratios:  q   1,   1   q   1,   2    . . . q   1   N(1)   (2)
 
     The influence level calculation unit  112  determines whether or not the higher nodes to which the bottom node is linked include a higher node that has a shareholding ratio in excess of 50% (step S 103 ). Upon determining “Yes” in step S 103 , the influence level calculation unit  112  performs a process of modifying the shareholding ratio of the higher node that has a shareholding ratio in excess of 50% and a process of excluding the higher nodes other than this higher node from the processing target (step S 104 ). Specifically, the influence level calculation unit  112  performs the process (3) below by designating the higher node for which the shareholding ratio is to be modified as a modification target higher node. 
       Math. 3 
       Rewrite Shareholding Ratio  q   1,   k  of Modification Target Higher Node  n   1   k  to 1, and Exclude Higher Nodes Other Than  n   1   k   (3)
 
     The influence level calculation unit  112 , upon determining “No” in step S 103 , proceeds to perform step S 105 . In this case, step S 104  is not performed. In the example of  FIG.  7   , the influence level calculation unit  112  determines “No” in step S 103  and proceeds to perform step  105 . 
     The influence level calculation unit  112  generates weighted paths for each of which an edge from the bottom node toward a higher node is assigned a shareholding ratio (step S 105 ). If step S 104  is performed, a single weighted path is generated. The weighted paths are given by (4) below. 
     
       
         
           
             
               
                 
                                    
                   
                     Math 
                     . 
                         
                     4 
                   
                 
               
               
                  
               
             
             
               
                 
                   	 
                   
                     Weighted 
                     ⁢ 
                         
                     Paths 
                     : 
                         
                     
                       n 
                       1 
                     
                     
                       ? 
                     
                     ⋯ 
                     ⁢ 
                        
                     
                       n 
                       1 
                     
                     
                       ? 
                     
                   
                 
               
               
                 
                   ( 
                   4 
                   ) 
                 
               
             
           
         
       
       
         
           
             
               ? 
             
             indicates text missing or illegible when filed 
           
         
       
     
     The influence level calculation unit  112  pushes the one or more weighted paths generated in step S 105  onto the stack S (step S 106 ). The influence level calculation unit  112  performs step S 106  and subsequently proceeds from “A” to step S 107  shown in  FIG.  14   . 
       FIG.  14    is a continuation (flow chart) to  FIG.  13   . The influence level calculation unit  112  obtains the top weighted path from the stack S (step S 107 ). The obtained weighted path is referred to as weighted path x. Weighted path x is given by (5) below. 
     
       
         
           
             
               
                 
                                    
                   
                     Math 
                     . 
                         
                     5 
                   
                 
               
               
                  
               
             
             
               
                 
                   	 
                   
                     
                       Weighted 
                       ⁢ 
                           
                       Path 
                       ⁢ 
                           
                       x 
                     
                     = 
                     
                       
                         n 
                         1 
                       
                       
                         ? 
                       
                       ⋯ 
                           
                       
                         ? 
                       
                     
                   
                 
               
               
                 
                   ( 
                   5 
                   ) 
                 
               
             
           
         
       
       
         
           
             
               ? 
             
             indicates text missing or illegible when filed 
           
         
       
     
     The influence level calculation unit  112  determines whether or not the highest node n k  is a shareholder in obtained weighted path x (step S 108 ). The influence level calculation unit  112 , upon determining “Yes” in step S 108 , pushes weighted path x obtained in step S 107  onto the path set P (step S 109 ). The highest node n k  in this case is a node corresponding to the ultimate controlling entity. Thereafter, the influence level calculation unit  112  proceeds to perform step S 116 . 
     The influence level calculation unit  112 , upon determining “No” in step S 108 , proceeds to perform step S 110 . The influence level calculation unit  112  obtains one or more higher nodes to which a processed node n k  is linked and the shareholding ratio(s) for the higher node(s), where the processed node is the highest node n k  of obtained weighted path x (step S 110 ). The one or more higher nodes to which the processed node n k  is linked and the shareholding ratio(s) of the higher node(s) are given by (6) below. 
       Math. 6 
       Higher Nodes:  n   k,   1   n   k,   2    . . . n   k,   N(k) , Shareholding Ratios:  q   k,   1   q   k,   2    . . . q   k   N(k)   (6)
 
     The influence level calculation unit  112  determines whether or not the higher nodes to which the processed node n k  is linked include a higher node that has a shareholding ratio in excess of 50% (step S 111 ). The influence level calculation unit  112 , upon determining “Yes” in step S 111 , performs a process of modifying the shareholding ratio of the higher node that has a shareholding ratio in excess of 50% and a process of excluding the higher node from the processing target (step S 112 ). Specifically, the influence level calculation unit  112  performs the process (7) below by designating the higher node for which the shareholding ratio is to be modified as a modification target higher node. 
       Math. 7 
       Rewrite Shareholding Ratio  q   k   1  of Modification Target Higher Node  n   k   1  to 1, and Exclude Higher Nodes Other Than  n   k   l   (7)
 
     If step S 112  has been performed, the influence level calculation unit  112  rewrites the remaining higher nodes and the shareholding ratios of these higher nodes as one or more higher nodes to which the processed node n k  is linked and the shareholding ratios related to the higher nodes. On the other hand, the influence level calculation unit  112 , upon determining “No” in step S 111 , proceeds to perform step S 113 . In this case, the influence level calculation unit  112  does not rewrite the one or more higher nodes to which the processed node n k  is linked and the shareholding ratio(s) of the higher node(s). 
     If there is a circulation node, the influence level calculation unit  112  performs a process of excluding the circulation node (step S 113 ). Specifically, if the one or more higher nodes to which the processed node n k  is linked includes weighted path x obtained in step S 107 , the influence level calculation unit  112  excludes this weighted path x. In other words, the influence level calculation unit  112  excludes a weighted path running from a higher node toward a lower node. In the example of  FIG.  7   , the path linking node  13  to node  4  is excluded. 
     A description is given of the process of excluding a circulation node. Suppose, as an example, that higher node Y owns shares in lower node X and also that lower node X owns shares in higher node Y. Suppose further that higher node Y has a shareholding ratio of Yq in lower node X and that lower node X has a shareholding ratio of Xq in higher node Y. In such a case, the indirect shareholding ratio of higher node Y in lower node X is given by Xq+Yq×Xq+Yq×Xq 2 +Yq×Xq 3 + . . . . 
     “Yq×Xq” in this formula represents the controlling power that controls Y via the path via which Y is controlled by X. If the controlling power is accepted, a loop is created in the process, which will increase the process volume for the influence level calculation unit  112 . The influence level calculation unit  112  therefore performs a process to exclude the circulation node. 
     If there is a circulation node, the influence level calculation unit  112  excludes the circulation node and rewrites the one or more higher nodes to which the processed node n k  is linked and the shareholding ratio(s) of the higher node(s). If there is no circulation node, the influence level calculation unit  112  does not rewrite the one or more higher nodes to which the processed node n k  is linked and the shareholding ratio(s) of the higher node(s). 
     The influence level calculation unit  112  adds a node and a shareholding ratio to the one or more higher nodes to which the processed node n k  is linked (step S 114 ). Hence, weighted path x is updated as in (8) below. 
     
       
         
           
             
               
                 
                                    
                   
                     Math 
                     . 
                         
                     8 
                   
                 
               
               
                  
               
             
             
               
                 
                   	 
                   
                     
                       
                         Weighted 
                         ⁢ 
                             
                         Path 
                         ⁢ 
                             
                         x 
                       
                       = 
                       
                         
                           n 
                           1 
                         
                         
                           → 
                           a 
                         
                         ⋯ 
                         
                           → 
                           a 
                         
                         
                           
                             ? 
                           
                           ⋯ 
                         
                       
                     
                         
                     , 
                     
                       
                         
                           n 
                           1 
                         
                         
                           ? 
                         
                         ⋯ 
                       
                       
                         → 
                         a 
                       
                       
                         
                           n 
                           k 
                         
                         
                           ? 
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   8 
                   ) 
                 
               
             
           
         
       
       
         
           
             
               ? 
             
             indicates text missing or illegible when filed 
           
         
       
     
     The influence level calculation unit  112  pushes updated weighted path x into the path set P (step S 115 ). The influence level calculation unit  112  determines whether or not the stack S has become empty (step S 116 ). The influence level calculation unit  112  takes the process back to step S 107  upon determining “No” in step S 116  and proceeds to perform step S 117  upon determining “Yes” in step S 116 . In other words, step S 107  to step S 116  are performed until the stack S becomes empty. 
     The influence level calculation unit  112  obtains each weighted path contained in the path set P and calculates the indirect shareholding ratio ISH of each node in the bottom node in the entity network (step S 117 ). Specifically, the influence level calculation unit  112  obtains all weighted paths contained in the path set P and defines the set of the obtained weighted paths as P(n k ). 
     The influence level calculation unit  112  then calculates the indirect shareholding ratio, ISH(k,1), of node n k  in node n 1  by using formula (9) below. 
       Math. 9 
         ISH ( k, 1)=Σ p∈p(nk) (Product of Shareholding Ratios Assigned to Edges Constrained in  p )  (9)
 
     The indirect shareholding ratios ISH shown in the example in  FIG.  12    are obtained in this manner. After performing step S 117 , the influence level calculation unit  112  ends the influence level calculation process using a bottom-up method. 
     Presentation Process 
     The indirect shareholding ratio ISH of each node in the entity network is obtained as described in the foregoing. The presentation processing unit  113  may cause, via the communications unit  130 , the display unit  240  of the terminal device  200  to display the entity network and the indirect shareholding ratios. 
       FIG.  15    is a diagram showing an exemplary presentation screen. The presentation processing unit  113  generates a screen showing each node in the entity network, the shareholding ratios assigned to the paths linking the nodes, and the indirect shareholding ratios ISH added to the respective nodes. The presentation processing unit  113  then controls to cause the display unit  240  of the terminal device  200  to display the generated screen. 
     Suppose, as an example, that the user operating the terminal device  200  has operated requesting a display of indirect shareholding ratios by using the operation unit  250 . Upon the operation unit  250  receiving this operation, the processing unit  210  controls to transmit the request for a display of indirect shareholding ratios to the server system  100  via the communications unit  230 . 
     The presentation processing unit  113  generates the above-described screen in response to the reception of the above-described request. The presentation processing unit  113  then transmits the generated screen to the terminal device  200  as a response and causes the display unit  240  of the terminal device  200  to display the generated screen. Hence, the influence level of each node in the entity network on node  1  can be visually presented to the user operating the terminal device  200 . 
     The presentation processing unit  113  may cause the display unit  240  of the terminal device  200  to display a screen emphasizing the one or more nodes that have an indirect shareholding ratio greater than or equal to a prescribed threshold value. The prescribed threshold value may be set to any value. For instance, when the prescribed threshold value is 0.5, the presentation processing unit  113  may generates a screen emphasizing nodes  2  and  10 , which have indirect shareholding ratios in excess of 0.5. 
     In this manner, information on those nodes that have high influence levels on node  1  can be presented to the user operating the terminal device  200  with good visibility. Alternatively, the presentation processing unit  113  may display emphasizing an indirect shareholding ratio corresponding to a node that has a high influence level. In this manner, information on the indirect shareholding ratio of a node that has a high influence level can be presented to the user operating the terminal device  200  with good visibility. The form of emphasis of nodes and indirect shareholding ratios is not limited to the screen example in  FIG.  15   . 
     Example of Influence Level Calculation Process where Control Propagation is Taken into Account 
     A description is given next of an influence level calculation process where control propagation is taken into account. A technique using control propagation may be referred to as a top-down method. The influence level calculation unit  112  may apply a technique using control propagation (top-down method) to a technique using the indirect shareholding ratio described above (bottom-up method). 
       FIG.  16    is a diagram illustrating another exemplary entity network. The entity network in the example of  FIG.  16    includes nodes  1  to  16 . The highest node is node  1 . The entity network in the example of  FIG.  16    differs from the entity network in the example of  FIG.  7   . In other words, node  1  to node  13  in the example of  FIG.  16    differ from node  1  to node  13  in the example of  FIG.  7   . 
     The influence level calculation unit  112  obtains a plurality of nodes that traces edges that have a shareholding ratio greater than or equal to a prescribed value u, starting at the highest node. The prescribed value a has a range of 0&lt;α&lt;1. The entity network in the example of  FIG.  16    shows a plurality of lower nodes to which node  1  (highest node) is directly or indirectly linked. 
     The lower nodes not linked to the highest node (node  1 ) are not subjected to the top-down method for this highest node. For instance, node  12  is only linked to node  9  and has an indirect shareholding ratio of 51%. Therefore, although there is another node that owns shares in node  12 , this other node is not directly or indirectly linked to node  1 . The other node is hence not shown in the example of  FIG.  16   . 
     For instance, by setting the prescribed value a to meet α≥0.5, a plurality of nodes that is effectively controlled by node  1  can be identified in the entity network in the example of  FIG.  16   . Suppose, as an example, that α=0.5. Of the nodes in the example of  FIG.  16   , nodes  7 ,  9 ,  10 ,  12 , and  13  are not found on the paths that trace edges that have a shareholding ratio greater than or equal to the prescribed value u. Therefore, the influence level calculation unit  112  excludes nodes  7 ,  9 ,  10 ,  12 , and  13  from the nodes and obtains the other nodes. 
     A typical entity network includes a large number of entities (nodes) and increasingly frequently includes a huge number of them. Therefore, the number of nodes to be processed by the technique using control propagation is preferably reduced before performing an influence level calculation process using the indirect shareholding ratio described above. 
     Accordingly, the influence level calculation unit  112  may perform an influence level calculation process using a bottom-up method only after narrowing down the nodes to be processed by a top-down method. The nodes to which the control of the highest node poorly propagates can be excluded from the influence level calculation process without seriously affecting the precision of the influence level calculation process. The influence level calculation unit  112  performs an influence level calculation process using a bottom-up method only after narrowing down the processing targets, which are the nodes of the entity network, by using a top-down method. In this manner, the influence level calculation process can be performed with a reduced process volume, but with high precision. 
     The prescribed value a is preferably less than 0.5 (less than half the maximum value of a) because many nodes in the entity network will be eliminated if the prescribed value a is excessively large. More preferably, α=⅓. 
     When α=⅓, it is possible to restrain excessively many nodes in the entity network from being eliminated and also to restrain the effect of the reduced process volume of the influence level calculation process from decreasing. 
     Suppose, as an example, that α=0.5 in the example of  FIG.  16   . In this case, nodes  7 ,  9 ,  10 ,  12 ,  13 , and  15  are eliminated. Therefore, the outputted nodes are those nodes that are shown in the example of  FIG.  17    when α=0.5. Suppose, as another example, that α=⅓ in the example of  FIG.  16   . In this case, only node  15  is eliminated. Therefore, the outputted nodes are those nodes that are shown in the example of  FIG.  17    when α=⅓. The nodes in the example of  FIG.  17    are obtained as a result of executing the flow chart in  FIG.  18    below. 
     It is understood from the description here that the effect of reducing the process volume in the case where α=⅓ is lower than the effect of reducing the process volume in the case where α=0.5, but higher than the effect of reducing the process volume in the case where no top-down method is applied. 
       FIG.  18    is a flow chart representing an exemplary flow of a process of implementing a technique using control propagation. The influence level calculation unit  112  initializes the node set in the highest level (step S 201 ). Here, as shown in  FIG.  16   , the node set in each hierarchical node level in the entity network is referred to as node set E m . The influence level calculation unit  112  makes settings, “m=1” and “flag=1,” in step S 201 . The flag assumes either a value of 0 or a value of 1. 
     The influence level calculation unit  112  renders node set E m+1  in a next hierarchical level ((m+1)-th hierarchical level) empty (step S 202 ). In this case, the influence level calculation unit  112  makes a setting, E m+1 =φ. 
     The influence level calculation unit  112 , for hierarchical level E m , obtains m+1 candidate nodes in a hierarchical level, which are companies (entities) having their shares owned by companies (entities) corresponding to the nodes that are elements of hierarchical level E m , at shareholding ratios in excess of a (step S 203 ). Specifically, the influence level calculation unit  112  obtains the nodes defined in (10) below and performs step S 203 . The nodes defined in (10) are the “m+1 candidate nodes in a hierarchical level.” 
       Math. 10 
       Of the nodes representing companies having their shares owned by the company represented by each element  n   m   k  of  E   m , where  E   m   −{n   m   1   n   m   2    . . . n   m   N(m) }, those nodes corresponding to companies having their shares owned by  n   m   k  at a shareholding ration in excess of α are { n   m   k (1,α) . . .  n   m   k ( l   n     m       k   ,α)}.
 
       The node set obtained by combining { n   m   k (1,α) . . .  n   m   k ( l   n     m       k   ,α)} for all  n   m   k  is defined as the  m+ 1 candidate nodes in a hierarchical level.  (10)
 
     Next, the influence level calculation unit  112  calculates the previously described nodes up to hierarchical level E m  in accordance with (11) below (step  204 ). 
       Math. 11 
       Set of previously described nodes up to hierarchical level  m=∪   l=1   m   E   1   (11)
 
     The influence level calculation unit  112  adds, to E m+1 , the set of nodes that remain when the previously described nodes up to hierarchical level m obtained in step S 204  are excluded from the m+1 candidate nodes in a hierarchical level obtained in step S 203  (step S 205 ). 
     The influence level calculation unit  112  increments m (m=m+1), and if E m  is empty, makes a setting, flag=0 (step S 206 ). 
     The influence level calculation unit  112  determines whether or not flag=0 (step S 207 ). The influence level calculation unit  112 , upon determining “No” in step S 207 , takes the process back to step S 202 . 
     If the flag is 0, the influence level calculation unit  112  determines “Yes” in step S 207 . In this case, the influence level calculation unit  112  returns the node set (12) below (step S 208 ). The influence level calculation unit  112  then ends implementing the flow chart in  FIG.  18   . 
       Math. 12 
       Node set returned in step  S 208=∪ l=1   m   E   l   (12)
 
     As described in the foregoing, the process can be streamlined by the influence level calculation unit  112  reducing the number of nodes to be processed using a top-down method in performing an influence level calculation process using a bottom-up method. 
     A description is given next of a variation example with reference to  FIG.  6 B . The influence level calculation unit  112  may change the technique of calculating the indirect shareholding ratio ISH when a given entity has its shares owned by another entity at a shareholding ratio in excess of ⅔. In the case of the example in  FIG.  19 A , entity B has a shareholding ratio in excess of 50%, but not in excess of ⅔, in entity C. In such a case, the influence level calculation unit  112  may calculate the indirect shareholding ratio ISH of entity B in entity A by additionally taking into account the indirect shareholding ratio of another entity. In the case of the example in  FIG.  19 B , the influence level calculation unit  112  may calculate, as the indirect shareholding ratio ISH of entity E in entity A, “9%” which remains when “40%,” which is the indirect shareholding ratio of entity D, and “51%,” which is the indirect shareholding ratio of entity B, are subtracted. 
     In the case of the example in  FIG.  19 B , entity B has a shareholding ratio of 80%, which is in excess of ⅔, in entity C. In such a case, entity B can be analyzed to completely control entity C. Therefore, the influence level calculation unit  112  may, similarly to the example in  FIG.  6 B , calculate the indirect shareholding ratio ISH of entity B in entity A to be 60% (=30%+1×30%). In this case, the indirect shareholding ratio ISH of entity E in entity A is 0%. 
     The present embodiment has been discussed in detail. A person skilled in the art will readily appreciate that numerous modifications can be made without substantially departing from the new matter and effects of the present embodiment. Accordingly, all such modifications are included in the scope of the present disclosure. For example, terms that appear at least once in the description or drawings along with another broader or synonymous term can be replaced by the other term in any part of the description or drawings. Also, all the combinations of the present embodiment and the modifications are encompassed in the scope of the present disclosure. Also, the configuration and operation of the information processing system, server system, and terminal device, among others, are not limited to those described in the present embodiment, and various modifications can be made.