노상규 교수

Abstract We develop a simulation model to examine conditions under which strategic groups emerge and their performance difference persists. In our model, mobility barriers, strategic interactions among high performers, dynamic capabilities (the mechanisms that allow winners to continue to survive), and boundary of rivalry are put together to derive their joint implications for the evolution of strategic groups. Not surprisingly, our model behavior shows that mobility barriers and strategic inter

The allocation of data and operations to nodes in a computer communications network is a critical issue in distributed database design. An efficient distributed database design must trade off performance and cost among retrieval and update activities at the various nodes. It must consider the concurrency control mechanism used as well as capacity constraints at nodes and on links in the network. It must determine where data will be allocated, the degree of data replication, which copy of the dat

Abstract Data envelopment analysis (DEA) has been widely used to evaluate the comparative efficiencies of production processes. Most of the DEA applications assume that production processes consist of one stage. However, many production processes such as IT investments have more than one stage. In a two‐stage production process, the first stage inputs produce intermediate outputs, which are used as inputs to the second stage to produce the final outputs. In such cases, using single‐stage DEA may

Theory suggests that semantic overload in database representations and query languages may be a significant contributing factor to difficulties in end-user access to corporate databases. With respect to join queries, two aspects of SQL-based relational database management systems are overloaded: (1) foreign key columns are overloaded to represent both attributes and relationships and (2) the WHERE clause in SQL is overloaded to include both selection criteria and join criteria. We experimentally

The information space of the Semantic Web has different characteristics from that of the World Wide Web (WWW). One main difference is that in the Semantic Web, the direction of Resource Description Framework (RDF) links does not have the same meaning as the direction of hyperlinks in the WWW, because the link direction is determined not by a voting process but by a specific schema in the Semantic Web. Considering this fundamental difference, the authors propose a method for ranking Semantic Web

Distributed database design is a difficult and complex process involving two major, interrelated problems. First, data must be allocated to nodes in the network. Second given such an allocation data must be efficiently accessed, processed, and possibly communicated to meet the retrieval and update requirements of the users. Both of these problems can be formulated as constrained, integer, optimization problems; both of which are NP-hard. Genetic algorithms provide an efficient search method for

Distributed database systems can yield significant cost and response time advantages over centralized systems for geographically distributed organizations. However, inappropriate design can result in high cost and poor response time. The design of efficient distributed databases is a complex task involving two interdependent problems: data allocation (where to place the data) and operation allocation (how and where to process the data). To be effective, a distributed database design approach mus

Distributed database systems can yield significant cost and performance advantages over centralized systems for geographically distributed organizations. The efficiency of a distributed database depends primarily on the data allocation (data replication and placement) and the operating strategies (where and how retrieval and update query processing operations are performed). We develop a distributed database design approach that comprehensively treats data allocation and operating strategies, ex

블로그, 페이스북, 트위터와 같은 SNS(Social Network Service)는 유저와 포스트를 노드로, 유저와 포스트, 포스트와 포스트, 또는 유저와 유저 사이에 형성되는 다양한 관계를 링크로 하는 그래프로 표현될 수 있다. 본 논문은 이러한 그래프 구조를 분석하여 다른 유저들의 생각과 행동에 영향을 미치는 영향 유저를 선별하는 방법에 대해 논한다. 기본적인 패러다임으로 기존의 투표성 개념이 아닌, 다양한 시맨틱 웹 자원의 중요도를 평가하기 위해 제안된 상호작용성 개념을 초기 SNS의 하나인 블로고스피어의 영향력 평가에 적용함으로써, 여러 모의 실험을 통해 그 타당성과 적용 가능성을 입증하였다. 모의 실험은 각 대안이 제공하는 결과의 타당성 정도에 따라 성능을 비교 분석할 수 있는 네트워크 모형을 디자인하여 사용하였다. 또, 이러한 네트워크 모형에 대한 링크 가중치 튜닝의 결과 변화를 살펴봄으로써, 가중치 조합의 차이에서 발생하는 실험 오차를 줄이고, 실제 적용의 용이함을 비

The efficiency and effectiveness of a distributed database depend\n\nprimarily on solving two interrelated design problems: data allocation,\n\nspecifying what data to replicate and where to store it, and operating\n\nstrategies, specifying where and how retrieval and update processes are\n\nperformed. We develop a distributed database design approach that\n\ncomprehensively addresses these problems, explicitly modeling their\n\ninterdependencies for both retrieval and update processing. We exte