• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권6호
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• pp.2658-2679
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• 2018

This paper proposes a novel Random Scheduling Algorithm based on Subregion Coverage (RSASC), to solve the SET K-cover problem (an NP-complete problem). SET K-cover problem distributes the set of sensors into the maximum number of mutually exclusive subsets (MESSs) in such a way that each of them can be scheduled for lifetime extension of WSN. Sensor coverage divides the target region into different subregions. RSASC first sorts the subregions in the ascending order concerning their sensor coverage. Then, it forms the subregion groups according to their similar sensor coverage. Lastly, RSASC ensures the K-coverage of each subregion from every group by randomly scheduling the sensors. We consider the target-coverage and area-coverage applications of WSN to analyze the usefulness of our proposed RSASC algorithm. The distinct quality of RSASC is that it utilizes less number of deployed sensors (33% less) to form the optimum number of MESSs with the higher computational speed (saves more than 93% of the time) as compared to the existing three algorithms.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1310-1311
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• 2003

Oil Field Geographical Information System (OFGIS) manages multiple spatial data, attribute data, and topographic data, which include almost every kind of ground info rmation and underground information. Subsystems managed by OFGIS include petroleum exploration subsystem (PESS), petroleum development and engineering subsystem (PDESS), petrochemical subsystem (PCSS), petroleum storage and transportation subsystem (PSTSS), petroleum sale subsystem (PSSS), etc. A basic OFGIS framework consists of oil field infrastructure coverage (OFIC), oil field specialized information coverage (OFSIC) and oil field synthesis and decision service coverage (OFSDSC). Basic function of OFGIS includes database management, geographic information management, spatial information processing and application.

• 한국항행학회논문지
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• 제24권3호
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• pp.212-217
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• 2020

최근 4차산업 혁명에 대한 관심과 더불어 자율주행 기술에 대한 요구가 높아지고 있다. V2X (vehicle to everything) 통신기술은 자율주행차량에 있어 핵심기술로서 유무선 망을 통해 차량, 인프라, 네트워크, 보행자 등과 같은 객체들과 정보를 교환하는 기술이다. 본 논문에서는 WAVE (wireless access in vehicular environment)와 LTE (long term evolution)를 복합설계하여 구현한 하이브리드 V2X 통신 시스템의 개발결과와 시스템의 성능을 확인하기 위해 커버리지 테스트를 수행한 결과를 제시한다. 커버리지 측정을 통해 하이브리드 V2X 통신 성능이 기존의 LTE나 WAVE의 단일 통신 시스템보다 통신 커버리지에 있어 우수하여 자율주행서비스에 효율적으로 적용 가능하다는 것을 보인다.

• 한국통신학회논문지
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• 제33권7B호
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• pp.567-574
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• 2008

본 논문에서는 OFDMA 방식을 사용하는 MMR (Mobile Multi-hop Relay) 시스템에서 RS (Relay Station)를 사용하여 커버리지 확장을 위한 최적화 방법을 제안하고 이에 대한 성능을 분석한다. 최적화 방법으로 최대 처리량을 만들기 위한 두 개의 주파수 할당 방법을 제안하고 각각의 할당 방법에 따른 BS의 처리량과 프레임 효율로 성능을 분석한다. 마지막으로 주파수 할당 방법에 따라 주어진 BS (Base Station)의 총 처리 용량(capacity)에서 RS의 최대 흡수를 분석한다. 결과를 통해 제안된 주파수 할당 방법이 커버리지 확장에 효율적이고, BS의 처리량도 증가시킬 수 있음을 알 수 있다. 또한 트래픽 밀도가 낮을 경우 MMR 시스템이 효율적임을 알 수 있다. 본 논문의 결과를 통해 향후 릴레이를 사용하여 휴대인터넷 서비스 지역과, 셀룰러 망을 넓히는데 있어 참고할만한 가이드라인이 될 수 있을 것이다.

• Journal of the Korean Statistical Society
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• 제29권1호
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• pp.17-27
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• 2000

In this paper, we develop noninformative priors that are used for estimating the reliability of stress-strength system under the Burr-type X model. A class of priors is found by matching the coverage probabilities of one-sided Bayesian credible interval with the corresponding frequentist coverage probabilities. It turns out that the reference prior as well as the Jeffreys prior are the second order matching prior. The propriety of posterior under the noninformative priors is proved. The frequentist coverage probabilities are investigated for samll samples via simulation study.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.125-128
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• 2000

In this paper, the handoff margins are analyzed using the propagation attenuation which is modeled as a product of the fourth power of the distant and a log-normal random variable whose standard deviation is 8 ㏈. The effect of handoff techniques on cell coverage for CDMA system are shown that soft handoff increases cell coverage relative to hard handoff. When the cell radius extends 5-10 % and the outage probability is 10 %, the relative cell coverage area is extended 3.22 ㏈-3.99 ㏈ and 2.55 ㏈-2.85 ㏈ with power control and without power control, respectively.

• 디지털콘텐츠학회 논문지
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• 제5권3호
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• pp.234-238
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• 2004

이동통신 시스템 설비는 크게 이동가입자의 접속을 위한 커버리지(Coverage)와 트래픽 증가시 소요되는 추가 트래픽 이용(Usage) 장비로 나눌 수 있으며, 이 분류에 따라 유선사업자가 이동사업자에게 지불하게 되는 접속료의 규모가 결정된다. 본 논문에서는 국내 유선사업자와 이동통신 사업자간의 접속료 산정을 위한 사전 작업으로서 투자요구에 따른 이동통신 시스템 설비를 분류하기 위한 새로운 기준을 제시한다. 새로이 제시하는 분류 기준에서는 시스템 설비의 용량(Erlang, throughput)과 가입자 수요를 이용하여 설비별로 커버리지의 비율을 적용함으로서 사업자간 양보를 통한 상호 합의점을 도출할 수 있다.

• Safety and Health at Work
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• 제2권2호
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• pp.148-157
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• 2011

Objectives: Although compensation for occupational injuries and diseases is guaranteed in almost all nations, countries vary greatly with respect to how they organize workers' compensation systems. In this paper, we focus on three aspects of workers' compensation insurance in Organization for Economic Cooperation and Development (OECD) countries - types of systems, employers' funding mechanisms, and coverage for injured workers - and their impacts on the actual frequencies of occupational injuries and diseases. Methods: We estimated a panel data fixed effect model with cross-country OECD and International Labor Organization data. We controlled for country fixed effects, relevant aggregate variables, and dummy variables representing the occupational accidents data source. Results: First, the use of a private insurance system is found to lower the occupational accidents. Second, the use of risk-based pricing for the payment of employer raises the occupational injuries and diseases. Finally, the wider the coverage of injured workers is, the less frequent the workplace accidents are. Conclusion: Private insurance system, fixed flat rate employers' funding mechanism, and higher coverage of compensation scheme are significantly and positively correlated with lower level of occupational accidents compared with the public insurance system, risk-based funding system, and lower coverage of compensation scheme.

• 한국농공학회논문집
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• 제62권4호
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• pp.87-97
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• 2020

The livestock infections had been happened seasonally, but they have gradually changed to be irrelevant to seasons and have an aspect to rapidly spread after outbreak. Especially in Korea, proactive disinfection measures are very important because the livestock farms are located densely so high as to accelerate the spread of disease between farms. livestock disease outbreaks like HPAI and FMD occurred with high probability due to vehicles visiting the farms, this study is to evaluate the efficiency of livestock vehicle disinfection systems by investigating the disinfectant coverage according to the type of vehicle disinfection system and the type of vehicle quantitatively. In field experiments, water-sensitive papers (WSPs) were attached to 21 locations on the surface of four vehicles (sedan, SUV, truck, and feed transport), respectively, and exposed to disinfectants while the vehicle was sprayed in two vehicle disinfection systems (tunnel type and simplified type). The WSPs were scanned and image-processed to calculate the disinfectant coverage. The results showed that the tunnel-type vehicle disinfection system had a better disinfection performance with an average coverage of 90.27% for all vehicles compared to 32.62% of the simplified type system. The problem of the simplified system was a wide coefficient of variation (1.05-1.31) of the disinfectant coverage between 21 locations indicating a need for further improvement of nozzle location and arrangement.

• JSTS:Journal of Semiconductor Technology and Science
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• 제2권2호
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• pp.132-140
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• 2002

This paper presents an ARM-based SOC bus transaction verification IP and the usage experiences in SOC designs. The verification IP is an AMBA AHB protocol checker, which captures legal AHB transactions in FSM-style signal sequence checking routines. This checker can be considered as a reusable verification IP since it does not change unless the bus protocol changes. Our AHB protocol checker is designed to be scalable to any number of AHB masters and reusable for various AMBA-based SOC designs. The keys to the scalability and the reusability are Object-Oriented Programming (OOP), virtual port, and bind operation. This paper describes how OOP, virtual port, and bind features are used to implement AHB protocol checker. Using the AHB protocol checker, an AHB simulation monitor is constructed. The monitor checks the legal bus arbitration and detects the first cycle of an AHB transaction. Then it calls AHB protocol checker to check the expected AHB signal sequences. We integrate the AHB bus monitor into Verilog simulation environment to replace time-consuming visual waveform inspection, and it allows us to find design bugs quickly. This paper also discusses AMBA AHB bus transaction coverage metrics and AHB transaction coverage analysis. Test programs for five AHB masters of an SOC, four channel DMAs and a host interface unit are executed and transaction coverage for DMA verification is collected during simulation. These coverage results can be used to determine the weak point of test programs in terms of the number of bus transactions occurred and guide to improve the quality of the test programs. Also, the coverage results can be used to obtain bus utilization statistics since the bus cycles occupied by each AHB master can be obtained.