• KSII Transactions on Internet and Information Systems (TIIS)
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• 제3권6호
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• pp.612-627
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• 2009

The high-level contribution of this paper is to illustrate the effectiveness of using graph theory tree traversal algorithms (pre-order, in-order and post-order traversals) to generate the chain of sensor nodes in the classical Power Efficient-Gathering in Sensor Information Systems (PEGASIS) data aggregation protocol for wireless sensor networks. We first construct an undirected minimum-weight spanning tree (ud-MST) on a complete sensor network graph, wherein the weight of each edge is the Euclidean distance between the constituent nodes of the edge. A Breadth-First-Search of the ud-MST, starting with the node located closest to the center of the network, is now conducted to iteratively construct a rooted directed minimum-weight spanning tree (rd-MST). The three tree traversal algorithms are then executed on the rd-MST and the node sequence resulting from each of the traversals is used as the chain of nodes for the PEGASIS protocol. Simulation studies on PEGASIS conducted for both TDMA and CDMA systems illustrate that using the chain of nodes generated from the tree traversal algorithms, the node lifetime can improve as large as by 19%-30% and at the same time, the energy loss per node can be 19%-35% lower than that obtained with the currently used distance-based greedy heuristic.

• 한국의류학회지
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• 제24권6호
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• pp.850-860
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• 2000

The purposes of this study was to provide the fundamental data for children's wear standardizing sizes of ready-made clothes by analyzing the elementary school girls’somatotype. The subjects for anthropometic measurements were 434 elementary school girls’by age groups < ‘(1st age(1ㆍ2 grade)’,‘2nd age(3ㆍ4 grade)’, and 3rd(5ㆍ6 grade)’ > living in Pusan. According to the analysis of upper bodies by the age groups 1. According to the analysis to draw somatometric factors by the age groups, sevenㆍseven and six actors in 1st . End and 3rd age groups are obtained from measurements of upper body. 2. The 1st & 2nd age groups: As the result of factor analysis for the factor, the first and second factors which explain more than 70% of the whole variance represent“horizontal size”and“vertical size”, which characterize more aspects of the body shape of girls at elementary school ages. 3. The 3rd age groups: As the result of factor analysis for the factor, 6 factor which explain 74.39% of variance were extracted form anthropometic data. The first factor represented the items of circumference, breadth and depth related to“sectional size the front length of the upper body”, The second factor described the items of "heights & the back length of the upper body”.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제23권8호
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• pp.492-497
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• 2017

하이퍼그래프는 노드와 여러 노드를 연결할 수 있는 하이퍼에지로 구성된다. 하이퍼그래프 분석을 위해 그래프 기본 연산 중 그래프 탐색을 사용할 수 있다. 일반 그래프에 사용되는 DFS, BFS 탐색방법을 하이퍼그래프에 그대로 적용하였을 시 여러 노드를 연결하는 하이퍼에지의 특성을 고려하지 않는 문제가 있다. 본 논문에서는 하이퍼그래프를 위한 DBMS인 hypergraphDB에 저장 된 그래프 탐색 시 에지 단위로 탐색 여부를 판단하는 방법을 제안하고, 제안 탐색 방법을 응용한 하이퍼그래프 분석 실험을 수행하였다. 실험을 통해 일반 그래프의 탐색 기법을 적용한 경우 보다 빠른 속도와 보다 적은 DB 접근 횟수로 그래프 분석 작업을 수행함을 보인다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.233-236
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• 1989

This paper deals with the expert system using network configuration and input information composed of protective relays and tripped circuit breakers. This system has knowlegebase independent on network dimension because network representation consists of the type of the matrix. Therefore, the knowlege of network representation is simplified, the space of knowlege is reduced, the addition of facts to the knowlege is easy and the expansion of facts is possible. In this paper, the network representation is defined to system matrix. This expert system based on the system matrix diagnoses normal, abnormal operations of protective devices as well as possible fault sections. The brach and bound search technique is used: breadth first technique mixed with depth first technique of primitive PROLOG search technique. This system will be used for real time operations. This expert system obtaines the solution using the pattern matching in working memory without no listing approach for rule control. This paper is written in PROLOG, the A.I. language.

• 한국통신학회논문지
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• 제18권3호
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• pp.425-438
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• 1993

기존의 논리 프로그램을 병렬로 실행하는 방법들은 병렬화의 제약이 되었던 공유 변수들의 생산변수-사용변수의 의존관계로 인해 서술적인 표현력이 강한 논리 언어에 잠재된 병렬성을 살리지 못했다. 이 논문에서는 공유 변수의 의존 관계를 제거하기 위해 논리 프로그램의 실행을 증명 나무의 생성 단계와 사실을 처리하는 두 단계로 분리하는 방법을 제시한다. 첫단계에서는 변수마다 유일한 번호를 붙여 증명 나무에 생성되는 연구들을 변수 수열로 차별화하고, 사실 처리시 각 변수의 값을 차별화된 변수로 구하여 증명 나무의 성공 여부를 확인할 수 있다. 따라서, 생산 변수가 값을 생산한 후 사용 변수가 있는 술어의 처리가 가능했던 기존의 병렬 처리 방식보다 더 높은 병렬성을 이룰 수 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권4호
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• pp.1643-1660
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• 2016

Connectivity and trust in social networks have been exploited to propose applications on top of these networks, including routing, Sybil defenses, and anonymous communication systems. In these networks, and for such applications, connectivity ensures good performance of applications while trust is assumed to always hold, so as collaboration and good behavior are always guaranteed. In this paper, we study the impact of differential behavior of users on performance in typical social network-enabled routing applications. We classify users into either collaborative or rational (probabilistically collaborative) and study the impact of this classification and the associated behavior of users on the performance of such applications, including random walk-based routing, shortest path based routing, breadth-first-search based routing, and Dijkstra routing. By experimenting with real-world social network traces, we make several interesting observations. First, we show that some of the existing social graphs have high routing costs, demonstrating poor structure that prevents their use in such applications. Second, we study the factors that make probabilistically collaborative nodes important for the performance of the routing protocol within the entire network and demonstrate that the importance of these nodes stems from their topological features rather than their percentage of all the nodes within the network.

• Journal of Information Processing Systems
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• 제16권1호
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• pp.201-209
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• 2020

The graph data structure is popular because it can intuitively represent real-world knowledge. Graph databases have attracted attention in academia and industry because they can be used to maintain graph data and allow users to mine knowledge. Mining reachability relationships between two nodes in a graph, termed reachability query processing, is an important functionality of graph databases. Online traversals, such as the breadth-first and depth-first search, are inefficient in processing reachability queries when dealing with large-scale graphs. Labeling schemes have been proposed to overcome these disadvantages. The state-of-the-art is the 2-hop labeling scheme: each node has in and out labels containing reachable node IDs as integers. Unfortunately, existing 2-hop labeling schemes generate huge 2-hop label sizes because they only consider local features, such as degrees. In this paper, we propose a more efficient 2-hop label size reduction approach. We consider the topological sort index, which is a global feature. A linear combination is suggested for utilizing both local and global features. We conduct experiments over real-world and synthetic directed acyclic graph datasets and show that the proposed approach generates smaller labels than existing approaches.

• 한국컴퓨터정보학회논문지
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• 제22권6호
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• pp.49-55
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• 2017

Robots, games and life applications have been developed while computer areas are developed. Moreover, various applications have been utilized for various users including the early childhood. Recently, smart phones have been dramatically used by various users including early childhood. Many applications need to find a path from a starting point to destinations. For example, without using real maps, users can find the direct paths for the destinations in realtime. Specifically, path exploration in game programs is so important to have accurate results. Nowadays, with these techniques, diverse applications for educations of early childhood have been developed. To deal with the functions, necessity of efficient path search programs with high accuracy becomes much higher. In this paper, we design and develop a friendly maze program for early childhood based on a path searching algorithm. Basically, the path of lineal distance from a starting location to destination is considered. Moreover, weight values are calculated by considering heuristic weighted h(x). In our approach, A* algorithm searches the path considering weight values. Moreover, we utilize depth first search approach instead of breadth first search in order to reduce the search space. so it is proper to use A* algorithm in finding efficient paths although it is not optimized paths.

• 한국정보과학회논문지:데이타베이스
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• 제34권2호
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• pp.119-132
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• 2007

유사 서브 시퀀스 검색은 분자 생물학 분야에서 사용되는 매우 중요한 연산이다. 본 논문에서는 대규모 DNA 시퀀스 데이타베이스를 처리 대상으로 하여 효율성과 정확도를 보장하는 실용적인 유사 서브 시퀀스 검색 기법을 제안한다. 제안된 기법은 이진 트라이를 인덱스 구조로 채택하여 DNA 시퀀스로부터 추출한 일정 길이의 윈도우 서브 시퀀스를 인덱싱 대상으로 한다. 유사 서브 시퀀스 검색 알고리즘은 기본적으로 다이나믹 프로그래밍 기법에 근거하여 이진 트라이를 루트로부터 너비 우선(breadth-first)방식으로 운행하며, 경로 상에 존재하는 모든 유사 서브 시퀀스를 검색해 낸다. 그러나 질의 길이가 윈도우의 크기보다 큰 일반적인 경우에는 질의를 일정 길이의 서브 시퀀스로 분해하여 각 서브 시퀀스에 대하여 유사 서브 시퀀스 검색을 수행한 후, 후처리 과정에 의하여 정확도에 손상 없이 이들 결과를 결합하는 분할 질의 처리 방식을 채택한다. 제안된 기법의 우수성을 검증하기 위하여, 실험을 통한 성능 평가를 수행한다. 실험 결과에 의하면 제안된 인덱스 기법은 접미어 트리에 비하여 약 40%의 작은 저장 공간을 가지고도 약 4-17배의 검색 성능의 개선 효과를 나타낸다. 또한 분할 질의 처리 방식에 의한 유사 서브 시퀀스 검색 알고리즘은 질의 길이가 긴 경우에도 효율적으로 동작하여 Suffix와 Smith-Waterman 알고리즘에 비하여 각각 수배에서 수십배의 검색 성능의 개선 효과를 나타낸다.

• 대한인간공학회지
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• 제33권3호
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• pp.215-227
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• 2014

Objective: The purpose of this study was to evaluate Korea's Honam express train's first- and second-class seat discomfort by using pressure measurement, subjective discomfort rating, and physical compatibility. Background: Over the years, the demand for an express train service is continually increasing. A comfortable ride is important to achieving passenger satisfaction. A train seat plays a significant role in fulfilling passenger seating comfort. With this in view, a field survey and pressure measurements were performed on the selected train seat. Method: The pressure ratio at the body-seat interface (thigh and buttock regions) was measured by the pressure mat system. The interface pressure ratio was calculated and compared. The subjective discomfort rating scale was used to evaluate the subjects' overall feeling. The dimensions of train seats were analysed according to the anthropometric and demographic characteristics of the population data from Size Korea. Results: The results highlighted that the interface pressure ratio was greater while participants sat on the second-class seat than the first-class seat in the left- and right-side thigh regions. Also the pressure ratio was greater for the participants in the 1st~25th percentile height groups (149.8~160.8cm). The subjects rated higher discomfort for the second-class seat than the first-class seat. The physical compatibility results showed that the second-class seat's breadth was inadequate for the 95th and 99th percentile male. Conclusion: Overall, interface pressure measurement, subjective discomfort score and physical compatibility results showed that the second-class seat was more uncomfortable for the passengers than the first-class seat. Application: The adopted methodologies could be used to measure the seating comfort of the train seats.