• Proceedings of the Korean Information Science Society Conference
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• 2012.06c
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• pp.1-3
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• 2012

RIF(Rule Interchange Format)는 시맨틱 웹의 구조중 규칙 계층을 담당하며 기존에 사용되고 있는 여러 상이한 규칙 언어들 간의 호환을 위한 표준 규칙 언어라고 할 수 있다. RIF는 W3C에서 승인되었다. 시맨틱웹을 위한 표준 온톨로지 언어로는 RDF와 OWL이 있으며, 최근 RDF 데이터에 대한 접근제어 (Access Control) 메커니즘과 관련하여 일부 학술적 연구가 수행되었다. 본 논문에서는 RDF 데이터와 결합될 수 있는 RIF 추론 규칙에 대해 이미 제안한 RDF 접근제어 메커니즘을 확장하고자 한다. RDF 데이터에 대해 명세된 접근 권한은 RIF 추론에 의하여 권한 충돌이 발생할 수 있고, 그로 인해 접근 권한은 허용되지 않을 수 있다. 본 논문에서는 어떤 조건에서 이러한 RIF 추론에 의한 권한 충돌이 발생하는 지를 분석하며, 이미 제안한 그래프 레이블링을 사용하는 충돌 발견 방법이 RIF 추론과 관련하여서도 효율적임을 보인다. 실험에서는 제안된 방법이, 비록 포함관계 추론에 특화 되었지만, Chase 알고리즘에 기반한 다른 연구에서의 방법보다 발견 시간을 크게 감소시킴을 보인다.

• Journal of Digital Contents Society
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• v.18 no.3
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• pp.535-542
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• 2017

The ubiquitous computing made it happen to easily take cognizance of context, which includes user's location, status, behavior patterns and surrounding places. And it allows providing the catered service, designed to improve the quality and the interaction between the provider and its customers. The personalized recommendation service needs to obtain logical reasoning to interpret the context information based on user's interests. We researched a model that connects to the practical value to users for their daily life; information about restaurants, based on several mobile contexts that conveys the weather, time, day and location information. We also have made various approaches including the accurate rating data review, the equation of Naïve Bayes to infer user's behavior-patterns, and the recommendable places pre-selected by preference predictive algorithm. This paper joins a vibrant conversation to demonstrate the excellence of this approach that may prevail other previous rating method systems.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2007.11a
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• pp.479-486
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• 2007

멘토링은 조직이나 사회 구성원들의 발전을 돕기 위한 프로그램으로서, 조언자, 상담자 및 후원자 역할을 하는 '멘토(mentor)'와 도움을 얻고자 하는 '멘티(mentee)'가 긴밀한 관계를 맺고 유지함으로써 상호 발전을 위해 수행된다. 현재 이루어지고 있는 대부분의 멘토링은 면대면 (face-to-face) 시스템이거나 웹 기반의 e-mentoring 시스템으로, 전자는 시간적 그리고 지역적 한계를 극복해야만 하고 후자는 멘토나 멘티가 멘토링 사이트에 접속하여 게시판을 확인하지 않으면 제대로 된 멘토링을 수행할 수 없다는 한계를 가지고 있다. 또한 멘토와 멘티의 매칭은 무작위로 이루어지거나 코디네이터라고 불리는 사람이 수행하기 때문에, 비용이 많이 소용될 뿐 아니라 개인적인 편견이나 오류가 개입될 여지가 상존한다. 이에 본 연구에서는 시간과 장소의 제약에 구애 받지 않는 u-Mentoring 시스템을 개발하고자 하며, 그 첫 단계로써 멘토와 멘티간의 매칭을 지원하는 새로운 알고리즘(M3 Algorithm, Mentor-Mentee Matching Algorithm)을 제안하고자 한다. 본 연구에서 제안하는 알고리즘은 매칭의 정확도와 멘토-멘티의 매칭 만족도를 높이기 위해 멘토-멘티 온톨로지(M-Ontology)와 사례기반추론 기법을 사용하였다. 즉, 멘토-멘티의 효과적인 매칭을 위해, 멘토-멘티간 매칭 사례가 없는 초기 단계에는 멘토와 멘티의 속성 비교를 통한 추천 방식을 사용하고, 멘토링이 종료되어 충분한 멘토-멘티간 매칭사례가 수집되면 그 결과를 재사용해 추후 매칭에 활용한다. 본 논문에서는 제안한 매칭 알고리즘이 내장된 u-Mentoring system의 포로토타입을 보여주고자 한다.

• Journal of KIISE
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• v.43 no.12
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• pp.1365-1375
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• 2016

One of the most important capabilities for autonomous service robots working in living environments is to recognize and understand the correct context in dynamically changing environment. To generate high-level context knowledge for decision-making from multiple sensory data streams, many technical problems such as multi-modal sensory data fusion, uncertainty handling, symbolic knowledge grounding, time dependency, dynamics, and time-constrained spatio-temporal reasoning should be solved. Considering these problems, this paper proposes an effective dynamic context management and spatio-temporal reasoning method for intelligent service robots. In order to guarantee efficient context management and reasoning, our algorithm was designed to generate low-level context knowledge reactively for every input sensory or perception data, while postponing high-level context knowledge generation until it was demanded by the decision-making module. When high-level context knowledge is demanded, it is derived through backward spatio-temporal reasoning. In experiments with Turtlebot using Kinect visual sensor, the dynamic context management and spatio-temporal reasoning system based on the proposed method showed high performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.8
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• pp.1259-1268
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• 2002

One of the major goals suggested in distributed system is to improve the performance of the system through the load balancing of whole system. Load balancing among systems improves the rate of processor utilization and reduces the turnaround time of system. In this paper, we design the rule of decision-making and information interchange based on knowledge based mechanism which makes optimal load balancing by sharing the future load state information inferred from past and present information of each nodes. The result of performance evaluation shows that utilization of processors is balanced, the processing time is improved and reliability and availability of systems are enhanced. The proposed mechanism in this paper can be utilized in the design of load balancing algorithm in distributed operating systems.

• Journal of KIISE
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• v.41 no.9
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• pp.674-685
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• 2014

The Knowledge service system needs to infer a new knowledge from indicated knowledge to provide its effective service. Most of the Knowledge service system is expressed in terms of ontology. The volume of knowledge information in a real world is getting massive, so effective technique for massive data of ontology is drawing attention. This paper is to provide the method to infer massive data-ontology to the extent of RDFS, based on cloud computing environment, and evaluate its capability. RDFS inference suggested in this paper is focused on both the method applying MapReduce based on RDFS meta table, and the method of single use of cloud computing memory without using MapReduce under distributed file computing environment. Therefore, this paper explains basically the inference system structure of each technique, the meta table set-up according to RDFS inference rule, and the algorithm of inference strategy. In order to evaluate suggested method in this paper, we perform experiment with LUBM set which is formal data to evaluate ontology inference and search speed. In case LUBM6000, the RDFS inference technique based on meta table had required 13.75 minutes(inferring 1,042 triples per second) to conduct total inference, whereas the method applying the cloud computing memory had needed 7.24 minutes(inferring 1,979 triples per second) showing its speed twice faster.

• Journal of Korean Society of Transportation
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• v.22 no.4 s.75
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• pp.159-173
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• 2004

This study utilizes the fuzzy logic and genetic algorithm to improve the existing incident detection models by addressing the problems associated with "crisp" thresholds and model transferability (applicability). The model's major components were designed to be a set of the fuzzy inference engines, and for the self-adaptation capability the genetic algorithm was introduced in optimization(or training) of the fuzzy membership functions. This approach is often called "the hybrid of fuzzy-genetic algorithm" The model performance was tested and found to be compatible with that of the existing well-recognized models in terms of performance measures such as detection rate, false alarm rate, and detection time. This study was not an effort for simple improvement of the model performance, but an experimental attempt to incorporate new characteristics essential for the incident detection model to be universally applicable for various roadway and traffic conditions. The study results prove that the initial objective of the study was satisfied, and suggest a direction that the future research work in this area must follow.

• Journal of Digital Contents Society
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• v.12 no.2
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• pp.217-223
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• 2011

AI(Artificial Intelligence) refers to the area of computer engineering and IT technology that focuses on the methodology and creation of intelligent agents. The Othello game is often produced with AI, since it is played with relatively simple rules on a board and on a limited space of 8 rows and 8 columns. Previous algorithms take longer time than desirable and often fail to face new circumstances, as they search for all the possible cases and rules. In order to solve this crucial weakness, we propose that a CBR algorithm be applied to Orthello. Case-Based Reasoning(CBR), is the process of solving new problems based on the solutions of the past similar problems. We can apply this process to Othello and expedite the process of computer reasoning for a solution to new cases based on the data from accumulated past cases. Then, these new solutions are dynamically added to the set of past cases so that it becomes harder for players(users) to be able to read the pattern. The proposed system in which a CBR algorithm is applied to the Othello game makes the computation process faster and the game harder to play.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.07a
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• pp.167-170
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• 2023

게임 플랫폼의 고도화와 게임 구현 기술의 발전을 통해 이루어지고 있는 개발 환경의 효율성 제고를 통해 이전에 게임의 구현 자체에 소요하는 시간을 게임 콘텐츠의 질적 향상을 위해 투입할 수 있는 여건이 형성되고 있다. 본 논문은 게임에서 등장하는 NPC가 보다 사실적인 추론을 통해 플레이어를 추적하도록 지정하는 알고리즘을 고수준의 카테고리로 구분하여 구현하여, 개발 과정에서의 NPC 구현에 효율성을 제고하는 기법을 제안한다. NPC가 플레이를 추적하는 스토리를 기반으로 하는 게임에서 NPC가 플레이어의 위치에 도달하기 위한 길찾기 알고리즘은 필수적이다. 일반적으로 사용되는 최단 거리 길찾기 알고리즘인 다익스트라(Dijkstra)의 경우, 효율적이지만 플레이어가 NPC의 경로를 예측 가능할 수 있기에 게임의 재미 향상에 걸림돌이 되는 단점이 있다. 본 논문에서는 최단 거리 길찾기를 구현하면서 다양한 게임 스토리 상의 설정으로 지정할 수 있는 다양한 방법론을 연구하였으며, 이를 구현하기 위한 고수준 길찾기에 대한 방법을 제시한다.

• Journal of Digital Convergence
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• v.15 no.4
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• pp.191-198
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• 2017

It is needed to support intelligent customized health information service for user convenience in PHR based Personal Health Care Service Platform. In this paper, we specify an ontology-based health data model for Personal Health Care Service Platform. We also design a knowledge search algorithm that can be used to figure out similar health record by applying machine learning and data mining techniques. Axis-based mining algorithm, which we proposed, can be performed based on axis-attributes in order to improve relevance of knowledge exploration and to provide efficient search time by reducing the size of candidate item set. And K-Nearest Neighbor algorithm is used to perform to do grouping users byaccording to the similarity of the user profile. These algorithms improves the efficiency of customized information exploration according to the user 's disease and health condition. It can be useful to apply the proposed algorithm to a process of inference in the Personal Health Care Service Platform and makes it possible to recommend customized health information to the user. It is useful for people to manage smart health care in aging society.