• 한국주거학회논문집
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• 제23권2호
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• pp.99-106
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• 2012

Compared to Packaged Terminal Air Conditioning Systems, Radiant Cooling Systems have the advantage of energy saving and thermal comfort. Thermally Activated Building System (TABS) is one of the radiant heating and cooling systems. The main difference between TABS and other radiant systems lies in the usage of the time-lag effect of storing heat energy in the concrete. Current energy usage in summer time is concentrated within a specific time by using Packaged Terminal Air-Conditioner (PTAC). Due to the time-lag effect of TABS, energy usage can be distributed to other time zones. To maximize this effect, it is important to determine the appropriate operating mode, which for TABS is dependent upon the cooling load generated by the occupancy schedule. In this study, occupancy schedules are determined for various residential types. The operating modes of TABS for these residential types are estimated by using a dynamic computational simulation method. The results indicate that the operating modes of TABS can be determined by residential type and occupancy schedule. The load handled ratio by TABS is set up differently according to the cooling load profile obtained from residential type and occupancy schedule. By using TABS, energy consumption could be reduced by 20% compared to PTAC.

• 한국시뮬레이션학회논문지
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• 제17권3호
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• pp.63-73
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• 2008

P제철은 수심, 하역장비 및 야드와의 Belt Conveyer 연결 가능성 등에 따라 3만톤급이 접안 가능한 선석에서부터 25만 톤급 선박이 접안 가능한 선석을 각각 운영하고 있다. 또한 3만톤급에서 25만 톤급의 Bulk선을 운영하고 있는데, 해상운임을 줄이기 위해 15만톤 이상의 대형선 배선비율을 증가하여 왔다. 그리고 선형별 흘수 및 선폭에 따라 접안 가능한 선석이 제한되기 때문에 대형선의 배선비율 증가는 특정 선석의 선석점유율 증가 요인이 되고, 선석점유율이 증가하면 결과적으로 대형선의 대기시간이 증가하여 체선료가 증가한다. 일반적인 대기이론에서 선석점유율이 일정 수준이 이상이 되면 대기시간이 급격이 증가하지만, P제철 원료부두의 경우 부두운영 및 선석운영 계획을 직접 수행함으로써 선박도착 및 하역생산성의 변동성이 적고 선박도착이 정시성이 확보되어 선석점유율 증가에 따른 선박대기 시간이 일반 대기이론에서 언급하고 있는 것보다 증가율이 낮다.

• Journal of Preventive Medicine and Public Health
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• 제22권2호
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• pp.189-196
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• 1989

In January 1988, district medical insurance plan was executed on a national scale in Korea. We conducted an evaluation of the impact of execution of district medical insurance plan on number of hospital patients: number of outpatients; and occupancy rate. This study was carried out by Box-Jenkins time series analysis. We tested the statistical significance with intervention component added to ARIMA model. Results of our time series analysis showed that district medical insurance plan had a significant effect on the number of outpatients and occupancy rate. Due to this plan the number of outpatients had increased by 925 patients every month which is equivalent to 8.3 percents of average monthly insurance outpatients in 1987, and occupancy rate had also increased by 0.12 which is equivalent to 16 percents of that in 1987.

• Journal of the Korean Institute of Landscape Architecture International Edition
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• 제1호
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• pp.183-191
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• 2001

The purpose of this study is to provide guidelines for planning, designing and managing neighborhood parks. Results form POE(Post-Occupancy-Evaluation) and RPOE(Re-Post-Occupancy-Evaluation) are analyzed for this study. Bundang Central Park in Bundang Newtown was selected for this study. This study compared the previous POE completed in 1996 with a RPOE conducted in 2001 to find out how the user, proximate environmental context, and the park administration changed in time and apply feedback for purposes of immediate problem solving. The results of this study showed that RPOE has to be initiated and utilized periodically as a device and the guideline for neighborhood park design, conservation, administration and operation.

• 대한교통학회지
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• 제14권1호
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• pp.135-154
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• 1996

This paper presents a heuristic algorithm for classifying vehicles using a single loop detector. The data used for the development of the algorithm are the frequency variation of a vehicle sensored from the circle-shaped loop detectors which are normal buried beneath the expressway. The pre-processing of data is required for the development of the algorithm that actually consists of two parts. One is both normalization of occupancy time and that with frequency variation, the other is finding of an adaptable number of sample size for each vehicle category and calculation of average value of normalized frequencies along with occupancy time that will be stored for comparison. Then, detected values are compared with those stored data to locate the most fitted pattern. After the normalization process, we developed some frameworks for comparison schemes. The fitted scales used were 10 and 15 frames in occupancy time(X-axis) and 10 and 15 frames in frequency variation (Y-axis). A combination of X-Y 10-15 frame turned out to be the most efficient scale of normalization producing 96 percent correct classification rate for six types of vehicle.

• 대한교통학회지
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• 제14권4호
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• pp.49-76
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• 1996

Until recently, the inductive loop detecters(ILD) have been used to collect a traffic information in a part of traffic manangment and control. The ILD is able to collect a various traffic data such as a occupancy time and non-occupancy time, traffic volume, etc. The occupancy time of these is very important information for traffic control algorithms, which is required a high accuracy. This accuracy may be improved by classifying a vehicle type with ILD. To classify a vehicle type based on a Analog Digital Converted data collect form ILD, this study used a typical and modifyed statistic method and General Learning Vector Quantization unsuperviser neural network model and a hybrid model of GLVQ and statistic method, As a result, the hybrid model of GLVQ neural network model is superior to the other methods.

• Journal of applied mathematics & informatics
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• 제28권1_2호
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• pp.275-282
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• 2010

This paper analyzes a discrete-time bulk-service queue with probabilistic bulk size, where the service process is interrupted by a Markov chain. We study the joint probability generating function of system occupancy and the state of the Markov chain. We derive several performance measures of interest, including average system occupancy and delay distribution.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1999년도 추계학술대회논문집
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• pp.131-140
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• 1999

Today freeway is experiencing a severe congestion with incoming or outgoing traffic through freeway ramps during the peak periods. Thus, the objectives of this study is to identify the traffic characteristics, analyze the relationships between the traffic characteristics and finally construct the delay predictive models on the ramp junctions of freeway with 70mph speed limit. From the traffic analyses, and model constructions and verifications for delay prediction on the ramp junctions of freeway, the following results were obtained: ⅰ) Traffic flow showed a big difference depending on the time periods. Especially, more traffic flows were concentrated on the freeway junctions in the morning peak period when compared with the afternoon peak period. ⅱ) The occupancy also showed a big difference depending on the time periods, and the downstream occupancy(Od) was especially shown to have a higher explanatory power for the delay predictive model construction on the ramp junction of freeway. ⅲ) The speed-occupancy curve showed a remarkable shift based on the occupancies observed ; Od < 9% and Od$\geq$9%. Especially, volume and occupancy were shown to be highly explanatory for delay prediction on the ramp junctions of freeway under Od$\geq$9%, but lowly for delay predicion on the ramp junctions of freeway under Od<9%. Rather, the driver characteristics or transportation conditions around the freeway were through to be a little higher explanatory for the delay perdiction under Od<9%. ⅳ) Integrated delay predictive models showed a higher explanatory power in the morning peak period, but a lower explanatory power in the non-peak periods.

• Journal of applied mathematics & informatics
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• 제32권1_2호
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• pp.129-136
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• 2014

One of the fundamental issues in the design of dynamic spectrum access policy is the modeling of the dynamic behavior of channel occupancy by primary users. Under a Markovian modeling of channel occupancy, a periodic sensing and greedy access policy is known as one of the simple and practical dynamic spectrum access policies in cognitive radio networks. In this paper, the primary occupancy of each channel is modeled as a discrete-time alternating renewal process with generally distributed on- and off-periods. A periodic sensing and greedy access policy is constructed based on the general channel occupancy model. Simulation results show that the proposed policy has better throughput than the policies using channel models with exponentially distributed on- or off-periods.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2003년도 정기총회 및 추계학술대회
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• pp.289-294
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• 2003

Purpose of this study is to supply data that need in qualitative improvement and plan for middle class through a post occupancy evaluation by the tenants in the rental apartment of national housing size. The results of this study are as follows; 1) Characteristic of household differ as the size tenants live in at present. But, usually characteristic of household was family life cycle was from child-rearing time to secondary education time, a family's number was 3${\sim}$4 person, and income per month was 1${\sim}$3 million won. 2) The satisfaction of whole and physical environment were satisfied more than average 3 points. However, the satisfaction of economic performance and administration environment were dissatisfied by average 3 points low. 3) Factors that affect in housing satisfaction were administration environment, the housing size, a family's number.