• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 2004년도 춘계공동학술대회 논문집
• /
• pp.660-663
• /
• 2004

The vehicle routing problem with time-varying speed(VRPTVS) is difficult to handle with regular problem solving approaches. An approach by partitioning the service zone into three sub-zones to reduce computing time and vehicle traveling distance is suggested in this paper. To develop a partitioning algorithm for VRPTVS, all customer locations are divided into two sections such as morning zone and evening zone, excluding daytime zone. And then each service zone is calculated to find a possible number of delivery points and chosen by time window having more number of possible delivery points by considering customer location and varying speeds. A temporary complete route that can serve all target points is developed by this procedure and a pairwise exchange method is applied to reduce the traveling time.

• 대한교통학회지
• /
• 제14권1호
• /
• pp.69-80
• /
• 1996

In most cities, travel demand is distributed along long corridors and its destinations tend to concentrate in a central business district. For this kind of many-to-one or one-to-many travel demand pattern, a zonal operation of buses can be an efficient bus operation technique in which a long bus-demand corridor is divided into service zones and each service zone is provided with its own bus route connecting the service zone and single destination separately. This paper develops models of the total transportation costs for a single-zone operation and 2-zonal operation of buses for a long demand corridor with single destination in terms of various cost parameters, demand density, bus operation speeds, and location of the boundary between two service zones. In this study the total transportation cost is assumed to consist of the bus operation cost, passenger waiting cost and passenger travel time cost. It was proved that a zonal operation of buses can be more efficient than a single-zone operation for certain circumstances of the system and an boundary condition between two operation techniques was obtained. Also, several case studies were performed for various values of the cost parameters.

• 한국도로학회논문집
• /
• 제16권3호
• /
• pp.109-117
• /
• 2014

PURPOSES : This study analyzes the available working time at work-zone on the Expressway in accordance to the new capacity manual. METHODS : Sensitivity analysis on variables were conducted to calculate the adjusted capacity at work-zone based on previous researches. RESULTS : The main factors which affect available working time at the work-zone were its capacity, number of lanes, terrain and lane width. Other factors have minimal effect on the available working time. Based on the analysis, a calendar of lane closures was suggested. CONCLUSIONS : A series of studies concluded that the capacity at work-zone in the new capacity manual reduced to 76-82% of the existing manual. As such, the available working time decreased. Furthermore, the factors affecting the available working time needs to be considered when making a plan to rehabilitate the distressed pavement.

• 한국통신학회논문지
• /
• 제29권8A호
• /
• pp.868-878
• /
• 2004

본 논문에서는 멀티미디어 트래픽을 효율적으로 서비스하기 위해 CDMA 순방향 링크에 제안되었던 Zone-based 전력제어 방식(1)의 역방향 링크 적용 타당성을 검증 및 분석하였다. Zone-based 전력제어 방식을 운용하기 위해서는 각 트래픽 채널에 할당되는 최대 전력량이 결정되어야 한다. 순방향 링크에서는 기지국의 전력 자원을 다수의 트래픽 채널이 공유하기 때문에 각 트래픽 채널에 할당 가능한 최대 전력 자원을 결정하는 메커니즘이 요구되지만, 역방향 링크에서는 서비스 단말별로 전송되는 트래픽 채널에 할당 가능한 최대 전력 자원이 결정되어져 있는 특성으로 인해 Zone-based 전력제어 방식이 쉽게 구현될 수 있다. 실험 결과는 Zone-based 전력제어 방식이 기존의 전력제어 방식에 비해 전력 소비량과 이동국의 트래픽 성능에 있어서 향상된 결과를 보여주었다. 결국 Zone-based 전력제어 방식은 멀티미디어 트래픽 환경에서 고속 데이터호의 서비스 반경을 셀의 전체 서비스 반경으로 확보할 수 있게 하고, 시스템 내에 생성되는 간섭 량을 억제하여 저속 음성호의 QoS도 적절히 보장해줄 수 있는 방안임을 확인하였다.

• 한국IT서비스학회지
• /
• 제10권4호
• /
• pp.243-258
• /
• 2011

With increasing interest in ubiquitous computing technology, an infrastructure for the short-distance wireless communication has been extended socially, bringing spotlight to the security system using the image or location. In case of existing security system, there have been issues such as the occurrences of blind spots, difficulty in recognizing multiple objects and storing of the unspecified objects. In order to solve this issue, zone-based location-estimation search system for the image have been suggested as an alternative based on the real-time location determination technology combined with image. This paper intends to suggest the search service for the image zone-based location-estimation. For this, it proposed the location determination algorism using IEEE 802.15.4/ZigBee's RSSI and for real-time image service, the RTP/RTCP protocol was applied. In order to combine the location and image, at the event of the entry of the specified target, the record of the time for image and the time of occurrence of the event on a global time standard, it has devised a time stamp, applying XML based meta data formation method based on the media's feature data based in connection with the location based data for the events of the object. Using the proposed meta data, the service mode which can search for the image from the point in time when the entry of the specified target was proposed.

• Journal of information and communication convergence engineering
• /
• 제9권2호
• /
• pp.244-250
• /
• 2011

Gossip is a well-known protocol which was proposed to implement broadcast service with a high reliability in an arbitrarily connected network of sensor nodes. The probabilistic techniques employed in gossip have been used to address many challenges which are caused by flooding in wireless sensor networks (WSNs). However, very little work has yet been done on real-time wireless sensor networks which require not only highly reliable packets reception but also strict time constraint of each packet. Moreover, the unique energy constraining feature of sensor makes existing solutions unsuitable. Combined with unreliable links, redundant messages overhead in real-time wireless sensor networks is a new challenging issue. In this paper, we introduce a Reliable Gossip Zone, a novel fine-tailored mechanism for real-time wireless sensor networks with unreliable wireless links and low packet redundancy. The key idea is the proposed forwarding probability algorithm, which makes forwarding decisions after the realtime flooding zone is set. Evaluation shows that as an oracle broadcast service design, our mechanism achieves significantly less message overhead than traditional flooding and gossip protocols.

• 한국측량학회지
• /
• 제29권1호
• /
• pp.91-100
• /
• 2011

소방서는 지역주민의 생명과 재산을 지키는 중요한 공공기반시설로 화재발생시 신속하게 대응하여 피해를 최소화할 수 있도록 최적의 입지에 위치해 있어야 한다. 하지만 접근성과 재난발생요소들을 고려하지 않는 소방서 입지는 편중된 소방서비스를 야기할 수 있다. 따라서 재난안전 사각지대 해소 및 소방서비스의 균등한 제공을 위해 효율적인 소방서 입지를 위한 서비스 분석이 필요하다. 특히 재난의 발생 기능성이 높은 취약지역을 최소화함으로서 효율적인 소방서비스를 제공하여야 한다. 본 연구에서는 효율적인 소방 서비스 제공을 위한 기초연구로서, 화재 등 재난발생의 취약성을 나타내는 값을 색인화한 지도와 소방서의 서비스지역을 나타내는 지도를 도출하는 방법을 제시한다. 중첩분석을 통해 서비스 지역을 나타내는 지도와 취약성을 나타내는 지도 사이의 공간적 분포의 불일치를 파악하고, 소방서비스의 취약지역을 도출한다.

• 사회복지연구
• /
• 제47권1호
• /
• pp.179-204
• /
• 2016

본 연구는 가족의 삶과 매우 밀접한 영역인 사회서비스의 사각지대의 개념을 정립하고, 사회서비스의 사각지대 실태를 아동가구, 노인가구, 장애가구, 빈곤가구로 분류하여 분석하였다. 분석을 위하여 사회서비스 수요공급실태조사의 가구용 조사 원자료를 활용하였고, 분석대상은 4,038명이다. 분석의 결과 대상의 포괄성 측면에서 사각지대 규모가 가장 큰 서비스는 고용지원서비스와 문화서비스인 것으로 나타났다. 이러한 결과는 가구 유형별로 큰 차이가 없었지만, 아동가구에서 주거지원 서비스, 노인가구에서 상담서비스에 대한 욕구가 충족되지 않는다는 것도 주목할 만하다. 급여의 충분성 측면에서 사각지대 정도가 가장 큰 서비스는 보건의료와 고용지원서비스인 것으로 나타났다. 이러한 결과를 가구 유형별로 봤을 때는 노인과 장애가구, 빈곤가구 모두 성인돌봄서비스가 서비스의 양적 충분성이 가장 낮은 것으로 나타났고, 아동가구는 지역사회서비스가 불충분한 것으로 나타났다. 이러한 분석 결과를 바탕으로 본 연구는 보건의료와 고용지원 서비스에 대한 확대, 현재 과잉공급되는 것으로 분석된 서비스에 대한 점검, 정부에서 제공하는 서비스 중 사각지대가 큰 것에 대한 민간조직의 집중 개입 등을 제안하였다.

• 산업공학
• /
• 제22권4호
• /
• pp.359-367
• /
• 2009

The vehicle travel time between the demand points in downtown area is greatly influenced by complex road condition and traffic situation that change real time to various external environments. Most of research in the vehicle routing problems compose vehicle routes only considering travel distance and average vehicle speed between the demand points, however did not consider dynamic external environments such as traffic situation by service time zones. A realistic vehicle routing problem which considers traffic situation of smooth, delaying, and stagnating by three service time zones such as going to work, afternoon, and going home was suggested in this study. A mathematical programming model was suggested and it gives an optimal solution when using ILOG CPLEX. A hybrid genetic algorithm was also suggested to chooses a vehicle route considering traffic situation to minimize the total travel time. By comparing the result considering the traffic situation, the suggested algorithm gives better solution than existing algorithms.

• 한국환경과학회지
• /
• 제4권5호
• /
• pp.61-61
• /
• 1995

Volatile organic compounds(VOCs) are of concern for their potential chronic toxicity, their suspected role in the formation of smog, and their suspected role in destruction of stratospheric ozone. Present study evaluated the exposures to selected VOCs in three microenvironments: 2 chlorinated and 5 aromatic VOCs in the indoor and outdoor air, and 5 aromatic VOCs in the breathing zone air of gas-service station attendants. With permissible Quality Assurance and Quality Control performances VOC concentrations were measured 1) to be higher in indoor air than in outdoor air, 2) to be higher in two Taegu residential areas than in a residential area of Hayang, and 3) to be higher in the nighttime than in the daytime. Among five aromatics, Benzene and Toluene were two most highly measured VOCs in breathing zone air of service station attendants. Based on the sum of VOC concentrations, the VOC exposure during refueling was estimated to be about 10% of indoor and outdoor exposures. For Benzene only, the exposure during refueling was estimated to cause about 52% of indoor and outdoor exposure. The time used to calculate the exposures was 2 minutes for refueling and 24 hours for indoor and outdoor exposures.