• 제목/요약/키워드: Least Cost Path

검색결과 52건 처리시간 0.032초

공간형태학적 특성 및 로드킬 자료를 활용한 산림서식지의 생태적 연결성 분석 (Analysis of Ecological Connectivity of Forest Habitats Using Spatial Morphological Characteristics and Roadkill Data)

  • 서현진;최철현;이승원;김진효
    • 생태와환경
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    • 제57권2호
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    • pp.75-82
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    • 2024
  • 이 연구는 경상북도 문경, 예천, 영주, 안동, 봉화 일대의 산림서식지 공간형태학적 패턴과 로드킬 발생 간의 특성을 확인하고, 서식지 간의 저항지도를 구축하여 최소비용거리 기반 연결성을 분석하였다. MSPA에서 도출된 산림서식지 Core와 로드킬 발생지점 간의 거리를 분석한 결과, Core로부터 약 74.11 m 떨어진 지역에서 로드킬 발생이 집중되었고, 대부분의 로드킬이 서식지로부터 360 m 이내에서 발생하는 것으로 확인되었다. 1 km2 이상의 Core인 핵심서식지 간의 연결성 분석 결과, 141개의 핵심서식지와 서식지 간의 최소거리 경로(path) 242개가 도출되었고, 통로거리(corridor distance) 값은 문경시가 가장 높게 분석되어 대상지 중 연결성이 가장 낮은 것으로 나타났다. 본 연구는 서식지 단절에 따른 생태계 연결성과 로드킬 문제를 분석하여, 생태통로 설치 등 생태계의 연결성 강화 및 서식지 복원 전략 개발을 위한 기초자료로 사용될 수 있을 것으로 기대된다.

Estimating the Effects of Multipath Selection on Concurrent Multipath Transfer

  • Wang, Jingyu;Liao, Jianxin;Wang, Jing;Li, Tonghong;Qi, Qi
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제8권4호
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    • pp.1406-1423
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    • 2014
  • Multi-mode device which combines multiple access technologies into a device will offer more cost-effective solution than a sole access implementation. Its concurrent multipath transfer (CMT) technology can transmit media flows over multiple end-to-end paths simultaneously, which is essential to select at least two paths from all available paths. At real networks, different paths are likely to overlap each other and even share bottleneck, which can weaken the path diversity gained through CMT. Spurred by this observation, it is necessary to select multiple independent paths as much as possible to avoid underlying shared bottleneck between topologically joint paths. Recent research in this context has shown that different paths with shared bottleneck can weaken the path diversity gained through CMT. In our earlier work, a grouping-based multipath selection (GMS) mechanism is introduced and developed. However, how to estimating the selection is still to be resolved. In this paper, we firstly introduce a Selection Correctness Index (SCI) to evaluate the correctness of selection results in actual CMT experiment. Therefore, this metric is helpful to discuss and validate the accuracy of the output paths. From extensive experiments with a realized prototype, the proposed scheme provides better evaluation tool and criterion in various network conditions.

수송모형이론에 의한 토공 운반 최적화 모델 및 프로그램 개발 (Developing an Optimization Model and Program for Planning the Earthwork Based Upon Transportation Theory)

  • 이승학;손재호;편재호;이승현
    • 한국건설관리학회논문집
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    • 제17권1호
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    • pp.101-109
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    • 2016
  • 도로공사 토공사 작업현장에서 수행되는 운반계획의 주요 목적은 절토량과 성토량 간의 균형을 맞추는 것과 운반비용, 운반거리를 최소화 하는 것이다. 토공사의 합리적인 운반계획은 공사비 및 공사기간에 직접적인 영향을 미치나, 기존의 토공사 운반계획은 현장관리자의 경험적 지식을 기반으로 토공 운반계획을 수립하는 실정이다. 이에 본 연구에서는 도로공사 토공사 작업현장의 토공물량 운반계획의 효율성 향상을 위해 활용할 수 있는 최적화 모델 개발 하였으며, 사례구간을 통해 본 연구를 적용시킨 결과 공사기간은 약 19%, 공사비는 약 11% 감소시킨 것으로 확인되었다.

혁신확산이론에 따른 스마트폰 지속사용의도에 관한 연구: 아이폰 사용자와 안드로이드 사용자의 충성도 비교를 고려하여 (A study on the continuous intention to use for Smartphone based on the innovation diffusion theory: Considered on the loyalty between users of iOS and Android platform)

  • 남수태;김도관;진찬용
    • 한국정보통신학회논문지
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    • 제17권5호
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    • pp.1219-1226
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    • 2013
  • 본 연구에서는 혁신확산이론을 기반으로 스마트폰 지속적 사용의도에 미치는 영향을 분석하고자 하였다. 또한 인구통계학적 특성을 이용하여 아이폰 사용자와 안드로이드 플랫폼 사용자 그룹의 충성도 차이가 있는지를 비교하였다. 예측변수로는 혁신확산이론에서 제시된 혁신성과 편리성, 경제적 비용, 사회적 영향, 커뮤니케이션 채널, 적합성 그리고 복잡성을 선택하였다. 연구대상은 부산 경남지역에 거주하는 스마트폰 사용자 278명이며 설문지를 통해 자료를 수집하였다. 인구통계학적인 분석은 IBM SPSS Statistics 19로 하였고 Smart PLS를 사용하여 확인적 요인분석과 변수들 간의 인과관계에 대한 경로분석을 실시하였다. 분석결과 복잡성을 제외한 스마트폰 지속사용의도와 충성도에 이르는 모든 경로가 유의미한 영향을 미치는 것으로 나타났다. 결과를 바탕으로 연구의 한계와 시사점을 제시하고자 한다.

SCM 성과 결정요인에 관한 통합적 연구: 공급업체 관점으로 (Studies on Determinant Factors of SCM Performance: From the Supplier Perspective)

  • 박광오;장활식
    • Asia pacific journal of information systems
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    • 제21권1호
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    • pp.1-27
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    • 2011
  • In an attempt to cope with widespread, dynamic, and accelerating changes in both internal and external business environments, companies often utilize information technologies such as SCM(Supply Chain Management). To date, SCM research has mainly focused on the effects of dynamic factors on SCM success and emphasized adoption strategies and critical success factors. Consequently, the effects of more static factors such as interdependency between SCM partners have been largely ignored. The purpose of this study, therefore, is to examine the effects of both dynamic and static factors on SCM performance by controlling for information quality and partnership quality. The five factors examined in this study include innovative ness, mutual dependency, quality of information, partnership quality, and SCM performance. All factors were examined from the perspective of part suppliers, except the mutual dependency which was examined from two aspects: supplier's dependency on customer and customer's dependency on supplier. Data was collected through five hundred survey questionnaires distributed to the part supplier companies that have implemented SCM systems for at least one year. As a result, a total of 170 valid responses were obtained. A structural equation research model was fitted using SAS 9.1.3 and SMART-PLS 2.0. The results of this study can be summarized as follows. First, innovativeness positively affected SCM information quality. SCM partnership quality, and ultimately SCM performance. The path coefficient between innovativeness and information quality was 0.387, with a t-value of 3.528. Innovativeness also had a positively direct effect on partnership quality. The path coefficient was 0.351 with a t-value of 3.366. The total effect of innovativeness on partnership quality was significant, although its indirect effect on partnership quality by altering information quality was negligible. The total indirect effect of innovativeness on SCM performance by affecting information quality and partnership quality was significant with a p-value of 0.014. Innovativeness played an important role in determining SCM performance. Second, mutual dependency showed no significant effect on SCM information quality. This result contradicts the earlier assertion that the more dependent two companies are, the more accurate and timely the information they exchange ought to be. This study showed that this may not be the case; a partner may provide information of poor quality even when it is strongly dependent on the other. Mutual dependency showed significant effect on partnership quality. However, when the mutual dependency perceived by suppliers was divided into two parts, one being a supplier's dependency on its customer company and the other being a customer's dependency on the supplier, the latter showed a significant impact on the perceived SCM partnership quality. This result indicates that a customer company can hardly improve the partnership quality perceived by suppliers by making them more dependent. It improves only when the suppliers perceive that their partners, typically having more bargaining power, are more dependent on them. The overall effect of mutual dependency of any kind on SCM performance, however, was not significant. Although mutual dependency has been mentioned as an important static factor influencing almost every aspect of cooperation on a supply chain, its influences may not be as significant as it was initially perceived to be. Third, the correlation between information quality and partnership quality was 0.448 with a p-value of less than 0.001. Information quality had a path coefficient of 0.256 to partnership quality with a t-value of 2.940. The quality of information exchanged between partners may have an impact on their partnership quality. Fourth, information quality also had a significant impact on SCM performance with a path coefficient of 0.325 with a t-value of 3.611. In this study, SCM performance was divided into four categories: product quality, cost saving, service quality, and order fulfillment. Information quality has Significant impacts on product quality, cost saving and service quality, but not on order fulfillment. Fifth, partnership quality, as expected, had a significant impact on SCM performance. The path coefficient was 0.403 with a t-value of 3.539. Partnership quality, like information quality, had positive impacts on product quality, cost saving and service quality, but showed no impact on order fulfillment. It seemed that order fulfillment is the hardest category of performance that SCM can satisfy. One major limitation of this study is that it surveyed only the suppliers. To better understand the dual aspects of SCM, it is important to survey both suppliers and the assemblers, especially in pairs. This research, to our best knowledge, was the first attempt to study the level of dependency between the two groups by measuring the dual aspects of SCM and studying mutual dependency from the categories of suppliers and assemblers each.. In the future, a more comprehensive and precise measurement of SCM characteristics needs to be achieved by examining from both the supplier's and assembler's perspectives.

GIS를 이용한 복합임도망의 계획 및 평가 (Planning and Evaluation of Synthetic Forest Road Network using GIS)

  • 권형근;서정일;이준우
    • 한국산림과학회지
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    • 제108권1호
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    • pp.59-66
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    • 2019
  • 이 연구는 체계적인 임내도로망의 구축을 위해 고규격 및 저규격의 임도를 포함하는 적정임도밀도를 산정한 후, 이를 토대로 구축한 복합임도망의 배치 효과를 5개의 비교임도망과 비교 평가하였다. 그 결과, 연구대상지의 적정임도밀도는 약 18.4 m/ha로 산정되었으며, 평균집재거리, 집재거리표준편차, 개발지수, 임도 우회계수 등의 지표에서 복합임도망이 가장 양호한 것으로 나타났다. 또한, 집재가능재적량과 집재가능면적에서 복합임도망은 간선임도망에 비해 약 4 %p 수준으로 비슷하게 나타났지만, 임도개설비용은 약 20 %p가 낮게 나타나 경제적 측면에서도 양호한 것으로 나타났다.

Multiple model switching adaptive control for vibration control of cantilever beam with varying load using MFC actuators and sensors

  • Gao, Zhiyuan;Huang, Jiaqi;Miao, Zhonghua;Zhu, Xiaojin
    • Smart Structures and Systems
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    • 제25권5호
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    • pp.559-567
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    • 2020
  • Vibration at the tip of various flexible manipulators may affect their operation accuracy and work efficiency. To suppress such vibrations, the feasibility of using MFC actuators and sensors is investigated in this paper. Considering the convergence of the famous filtered-x least mean square (FXLMS) algorithm could not be guaranteed while it is employed for vibration suppression of plants with varying secondary path, this paper proposes a new multiple model switching adaptive control algorithm to implement the real time active vibration suppression tests with a new multiple switching strategy. The new switching strategy is based on a cost function with reconstructed error signal and disturbance signal instead of the error signal from the error sensor. And from a robustness perspective, a new variable step-size sign algorithm (VSSA) based FXLMS algorithm is proposed to improve the convergence rate. A cantilever beam with varying tip mass is employed as flexible manipulator model. MFC layers are attached on both sides of it as sensors and actuators. A co-simulation platform was built using ADAMS and MATLAB to test the feasibility of the proposed algorithms. And an experimental platform was constructed to verify the effectiveness of MFC actuators and sensors and the real-time vibration control performance. Simulation and experiment results show that the proposed FXLMS algorithm based multiple model adaptive control approach has good convergence performance under varying load conditions for the flexible cantilever beam, and the proposed FX-VSSA-LMS algorithm based multiple model adaptive control algorithm has the best vibration suppression performance.

국부발진기에서의 누설신호의 새로운 제거방식 (A Novel Method to Reduce Local Oscillator Leakage)

  • 이병제;강기조
    • 한국전자파학회논문지
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    • 제11권2호
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    • pp.294-301
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    • 2000
  • RF(radio frequency) 시스템의 송신탄을 설계할 때 고려해야 할 중요한 요소 중의 하나인 EMI(Electro magnetic interference)의 규격시험에서 항상 문제시되는 것이 송신기의 출력 스펙트럼에서 나타나는 불요 신호(Spurious interference) 이다. 이 불요 성분들 중 특히 문제가 되고 있는 것이 국부발진기(LO; Local oscillator)로부터 누설되는 LOL(Local oscillator leakage) 성분이다. 이 LOL성분은 국부발진기에서 누설(leakage)되어 RF단의 증폭기를 통하여 증폭되어 최종 출력에서 매우 높은 선호의 크기로 나타난다. 일반적으로 LOL을 제거하기 위해 서 너치필터(Notch filter) 또는 대역통과필터 (Band pass filter)를 사용해왔다. 본 논문에서는 국부발진기로부터 누설되는 불요 성분, 즉 LOL성분을 제거하는 방법으로 LOL과 동일한 크기를 가지고 위상 차이가 $180^{\circ}$인 신호를 국부발전기의 출력에서 만들어 믹서( Mixer)의 출력단에 더함으로써 LOL성분을 효과적으로 제거한다. 본 방 식을 무선랜(WLAN; Wireless 1$\infty$al area network) 시스템에 적용한 결과. 기존의 방식보다 30 dB 이상 LO 누설선호플 감쇄시킬 수 있었다 또한 본 방식은 RF 시스댐을 소형화 및 MMIC(Monolithic microwave integrated C circuit)화 할 경우 종전의 방법보다 효과적일 것으로 기대된다.

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무선 센서 네트워크에서의 비트맵 브로드캐스팅 라우팅 알고리즘 (A routing Algorithm by Broadcasting a Bitmap in Wireless Sensor Networks)

  • 정상준
    • 한국통신학회논문지
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    • 제31권5A호
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    • pp.459-468
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    • 2006
  • 현재의 센서 네트워크에서의 라우팅은 센서 노드의 한정된 에너지를 고려하여 네트워크의 유지를 최대화하기 위한 방향으로 라우팅 경로를 설정하고 있다. 기존의 라우팅 알고리즘은 센서 노드의 한정된 자원과 이동성을 지원하기 위해 라우팅 테이블을 가지지 않고 라우팅이 이루어질 때마다 라우팅 경로를 찾아 주어진 경로로 라우팅을 수행하는 방법을 사용하고 있다. 센서 네트워크에서 베이스 스테이션 기능을 가지는 싱크 노드는 이동성을 보장 받지만 센서 노드 자체는 비이동성을 가정하는 경우가 일반적이다. 따라서 한정된 자원 내에서 라우팅을 수행하도록 라우팅 테이블의 크기를 최소화하는 방안이 제시된다면 새로운 라우팅 기법을 고려해 볼 수 있다. 본 논문은 라우팅 테이블의 크기를 최소화하는 방법으로, 비트맵을 구성하여 라우팅을 수행하는 새로운 라우팅 알고리즘을 제안한다. 각 노드는 이웃 노드와의 연결 정보를 비트로 표현하여 비트맵을 구성하는데, 전송에 필요로 하는 에너지를 최소화 하도록 이웃 노드에게 단 한번의 브로드캐스트를 수행한다. 그 결과, 모든 노드의 전체 네트워크의 링크 정보를 가지는 것이 아니라 부분적인 링크 정보를 가지게 된다. 링크 정보는 싱크 노드에 의해 만들어지므로, 부분적인 네트워크 연결 정보이지만 각 노드는 싱크 노드로 보고될 경로를 가질 수 있게 된다. 단 한번의 브로드캐스트이므로 메시지 전송 횟수를 최소할 수 있다. 즉, 센서 노드에서 메시지를 전송할 때 가장 많은 에너지를 소모하게 되는데, 경로 설정에 필요한 에너지를 줄이는 것은 노드가 가지는 한정된 에너지의 소모를 줄일수 있게 되어 네트워크의 생존 시간을 늘릴 수 있다는 것을 의미한다. 제안하는 라우팅 알고리즘은 기존의 라우팅 알고리즘에 비해 10% 정도의 메시지 전송 횟수를 줄일 수 있다.

수도권 개발제한구역의 경관생태학적 가치평가 (An Assessment of Landscape Ecological Value of Greenbelt Areas in the Seoul Metropolitan Area)

  • 오규식;박지혜;이동우
    • 환경영향평가
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    • 제20권6호
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    • pp.867-878
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    • 2011
  • Development restriction areas (greenbelt areas) of Korea were recognized in 1970 as a means to control urban sprawl and conserve the natural environment. Although there have been some achievements, for a long time many planners and residents have requested a redefining of the green belt due to individual property rights restrictions and urban management problems. In fact, a lot of the greenbelt area is being destroyed by urban development. Therefore, conservation of ecological spaces in the green belt is needed to maintain urban naturalness. In this regard, this study suggests efficient methods to manage the greenbelt through the adoption of a landscape ecological value assessment. The greenbelt of the Seoul Metropolitan Area (SMA) is represented as the case study because there has been mounting pressure to develop the area in Korea. In this study, the assessment of the landscape ecology in the greenbelt area focuses on landscape structure and function. The assessment consists of the following steps: First, patches were derived by NDVI analysis using landsat remote sensing data. Second, characteristics of the patches were quantified by analyzing the landscape structure, such as patch size and shape index. Lastly, the gravity model and least cost path analysis to assess connectivity were applied to evaluate the landscape function in the green belt areas. The assessment result showed that 48.45% of green belt area should be conserved to maintain ecological stability and function. Moreover, major ecological networks were identified near the large patches in the northern and southern areas. However, relative low ecological values were identified in the western part of the green belt area due to the lack of green spaces. Furthermore, some development plans in the green belt were also identified near the conservation area. Based on these results, the restoration needed areas to enhance ecological value in green belt were displayed. This study suggests efficient management of the greenbelt area, which is disappearing as a result of urban development. The area for conservation chosen in this study should be managed carefully in urban planning. Finally, the results of this study can be used in green belt polices and plans for the promotion of ecological naturalness and stability.