• ETRI Journal
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• 제42권1호
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• pp.36-45
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• 2020

A priority-based data communication approach, developed by employing cognitive radio capacity for sensor nodes in a wireless terrestrial sensor network (TSN), has been proposed. Data sensed by a sensor node-an unlicensed user-were prioritized, taking sensed data importance into account. For data of equal priority, a first come first serve algorithm was used. Non-preemptive priority scheduling was adopted, in order not to interrupt any ongoing transmissions. Licensed users used a nonpersistent, slotted, carrier sense multiple access (CSMA) technique, while unlicensed sensor nodes used a nonpersistent CSMA technique for lossless data transmission, in an energy-restricted, TSN environment. Depending on the analytical model, the proposed wireless TSN environment was simulated using Riverbed software, and to analyze sensor network performance, delay, energy, and throughput parameters were examined. Evaluating the proposed approach showed that the average delay for sensed, high priority data was significantly reduced, indicating that maximum throughput had been achieved using wireless sensor nodes with cognitive radio capacity.

• 정보처리학회논문지A
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• 제16A권3호
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• pp.217-222
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• 2009

우선순위 큐는 스케줄링, 정렬, 유전자 검색과 같은 우선순위에 따른 검색, 최단거리 계산과 같은 응용에 사용될 수 있다. 본 논문에서 제안하는 배열을 이용한 양단 우선순위 큐 자료구조는 삽입과 삭제 연산에 각각 O(1) 전이시간과 O(logn) 시간이 걸린다. 본 저자가 알고 있는 한, 지금까지의 배열을 이용한 양단우선순위 큐 알고리즘은 삽입과 삭제에 모두 O(logn) 시간이 걸린다.

• 한국콘텐츠학회논문지
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• 제20권8호
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• pp.637-644
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• 2020

VANET (Vehicular Ad Hoc Networks)은 차량 간, 차량과 인프라 간의 네트워크이다. 높은 이동성, 이동 제한, 장애물에 의한 신호 방해와 같은 VANET 고유의 특성은 안정적인 VANET 서비스 제공을 어렵게 한다. 이를 해결하기 위해, 본 논문에서는 기존 버스 기반 클러스터링을 개선한, 차량 종류 기반 우선순위 클러스터 방법을 제시한다. 제안 알고리즘은 차량 종류, 예상 통신 수명, 주변 노드 링크 차수를 바탕으로 우선순위, 링크 품질, 연결성을 평가해 클러스터를 구성한다. 차량의 종류를 바탕으로 미리 결정된 우선순위를 활용함으로써 클러스터 헤드 선택을 단순화하고 클러스터 커버리지를 높이고자 한다. 제안 알고리즘은 커넥티드카 환경에서 안정적인 서비스를 제공하는데 기여함으로써 다양한 서비스 활성화의 기반이 될 것으로 기대된다.

• 한국통신학회논문지
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• 제14권5호
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• pp.453-461
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• 1989

Bux의 우선도가 없는 토큰링 LAN의 해석 결과와 Cobham의 HOL 우선도의 해석 결과를 사용해서 패킷에 우선도가 있는 토큰링 LAN의 각 노드에서의 각 우선도에 대한 평균대기시간을 근사적으로 해석하였다. IEEE 802.5에 제시된 토큰링 LAN에서의 우선도 예약전송방법은 사용하지 않았다. 본 논문에서 해석한 수학적 결과와 시뮬레이션 결과를 비교하여 +-5%정도의 상대오차율을 확인하였다. 트래픽의 세기, 노드수, 패킷길이, 전송속도, 회선길이, 토큰검색시간, 우선도 동급수, 트래픽 집중율 변화에 따른 각 우선도의 지연을 분석하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권4호
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• pp.1337-1358
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• 2015

In this paper, we present an analytical and simulated study on the performance of adaptive vehicular ad hoc networks (VANET) priority based on Transmission Distance Reliability Range (TDRR) and data type. VANET topology changes rapidly due to its inherent nature of high mobility nodes and unpredictable environments. Therefore, nodes in VANET must be able to adapt to the ever changing environment and optimize parameters to enhance performance. However, there is a lack of adaptability in the current VANET scheme. Existing VANET IEEE802.11p's Enhanced Distributed Channel Access; EDCA assigns priority solely based on data type. In this paper, we propose a new priority scheme which utilizes Markov model to perform TDRR prediction and assign priorities based on the proposed Markov TDRR Prediction with Enhanced Priority VANET Scheme (MarPVS). Subsequently, we performed an analytical study on MarPVS performance modeling. In particular, considering five different priority levels defined in MarPVS, we derived the probability of successful transmission, the number of low priority messages in back off process and concurrent low priority transmission. Finally, the results are used to derive the average transmission delay for data types defined in MarPVS. Numerical results are provided along with simulation results which confirm the accuracy of the proposed analysis. Simulation results demonstrate that the proposed MarPVS results in lower transmission latency and higher packet success rate in comparison with the default IEEE802.11p scheme and greedy scheduler scheme.

• 한국환경보건학회지
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• 제44권1호
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• pp.76-89
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• 2018

Background: Exposure to endocrine disrupting chemicals (EDCs) has been considered one of the main causes of a range of endocrine diseases in modern society. An EDC priority list considering exposure, toxicity, and societal concern should be established for EDC management. Methods: The chemical ranking and scoring (CRS) system for EDCs was based on exposure, toxicity,and societal concern. The exposure score system was based on usage, circulation volume, bioaccumulation, and detection in consumer products. The toxicity score system was based on carcinogenicity and reproductive and developmental toxicity. The societal concern score system was based on domestic or international regulations and mass media reports. Results: A total of 165 EDCs were considered in the CRS system. The top-five priority EDCs were Bis(2-ethylhexyl) phthalate (DEHP), Benzene, Bisphenol A, Dibutyl phthalate (DBP) and Trichloroethylene. Phthalates, bisphenols and parabens were identified as priority chemical groups. Conclusion: We developed a CRS system for EDCs to identify priority EDCs for management. This will be a foundation to provide an EDC management plan based on scientific decision-making.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 추계학술대회
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• pp.102-105
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• 2010

전통적인 Pub/Sub(Publish/Subscribe) 시스템은 중개자(Broker)를 통해 출판자(Pub)의 출판조건(Event)에 매칭되는 구독자(Sub)의 모든 구독조건(Subscription)들을 검색한다. 즉, 출판조건과 구독조건간의 매칭의 정도는 고려되지 않고, 매칭의 유무만을 판단한다. 매칭된 구독조건 간에도 우선순위가 존재할 수 있다. 따라서 기존 Pub/Sub 시스템의 기능을 확장한 우선순위 Pub/Sub 시스템이 필요하다. 이 논문에서는 구독조건간의 우선순위를 결정하기 위해 검색결과의 정확도를 정의 하고 우선순위에 따라 구독조건을 검색할 수 있는 정확도 기반 우선순위 검색기법을 제안한다. 본 검색기법은 IS-Lists(Interval Skip Lists)를 기반으로 동작하며, 정확도를 통해 정렬된 검색 결과를 얻을 수 있다.

• 한국정밀공학회지
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• 제15권6호
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• pp.107-115
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• 1998

A path planning using potential field method is very useful for the real-time navigation of mobile robots. However, the method needs high modeling cost to calculate the potential field because of complex preprocessing, and mobile robots may get stuck into local minima. In this paper, An efficient path planning algorithm for multiple mobile robots, based on the potential field method, was proposed. In the algorithm. the concepts of subgoals and obstacle priority were introduced. The subgoals can be used to escape local minima, or to design and change the paths of mobile robots in the work space. In obstacle priority, all the objects (obstacles and mobile robots) in the work space have their own priorities, and the object having lower priority should avoid the objects having higher priority than it has. In this paper, first, potential based path planning method was introduced, next an efficient collision-avoidance algorithm for multiple mobile robots, moving in the obstacle environment, was proposed by using subgoals and obstacle priority. Finally, the developed algorithm was demonstrated graphically to show the usefulness of the algorithm.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.1057-1058
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• 2009

• 한국건축시공학회지
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• 제12권1호
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• pp.10-21
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• 2012

As one of the key IT applications, the project management information system (PMIS) played a significant role in construction management processes in Korea. On increasing use of PMIS, regular quality assessment to identify user's requirements of PMIS is necessary. However, there have been rare research efforts for quality assessment for the construction PMIS. This paper aims to propose a priority index of quality improvement for construction PMIS using the importance and satisfaction measures and to verify the discrimination power of the priority index by comparing it with other quality improvement priority index. In addition, this paper discusses some possible ways of PMIS quality improvement. The analysis of quality improvement priority was based on a questionnaire responded by 253 PMIS users (construction managers and constructors). The methods of PMIS improvement were based on the interviews with eight experts. These findings would be the foundation of further researches on PMIS quality improvement. However, more efforts are required to enhance the priority index, in terms of reflecting weighted values of quality assessment factors.