• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.171-174
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• 2000

In this paper, we improve statistical-model-based speech detector using the probability that a speech occupies a frequency bin. While the previous method assumes speech energy occupies all the frequency components and use them with equal weights in the likelihood ratio test for speech detection, the proposed method assumes speech energy occupies just some frequency componets and use them with different weights in accordance with the probabilities of spectral occupancy in the test. The probability is iteratively up-dated for speech frames to contribute to the likelihood ratio test. The proposed method well reflects the characteristic distribution of speech spectrum, and yields better detection performance.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2003.05a
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• pp.115-120
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• 2003

This study aims at calculating berth length required of the given volume of containers. For this, unlike previous studies assuming 300,000 TEU per berth as the capacity of a berth, this study attempts to apply more realistic situation such as the distribution of vessel size, lifts per vessel, berth time by vessel size, and average berth occupancy ratio. the result are compared with that of Pusan New port planning.

• Korean Journal of Environment and Ecology
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• v.37 no.6
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• pp.429-438
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• 2023

The forest in the lower Tumen River serves as an important ecosystem spanning the territories of North Korea, Russia, and China, and it provides habitat and movement corridors for diverse mammals, including the endangered Amur tiger (Panthera tigris) and Amur leopard (Panthera pardus). This study focuses on the Mijiang area, situated as a potential ecological corridor connecting North Korea and China in the lower Tumen River, playing a crucial role in conserving and restoring the biodiversity of the Korean Peninsula. This study aimed to identify mammal species and estimate their relative abundance, occupancy, and distribution based on the 48 camera traps installed in the Mijiang area from May 2019 to May 2021. The results confirmed the presence of 18 mammal species in the Mijiang area, including large carnivores like tigers and leopards. Among the dominant mammals, four species of ungulates showed high occupancy and detection rates, particularly the Roe deer (Capreolus pygargus) and Wild boar (Sus scrofa). The roe deer was distributed across all areas with a predicted high occupancy rate of 0.97, influenced by altitude, urban residential areas, and patch density. Wild boars showed a predicted occupancy rate of 0.73 and were distributed throughout the entire area, with factors such as wetland ratio, grazing intensity, and spatial heterogeneity in aspects of the landscape influencing their occupancy and detection rates. Sika deer (Cervus nippon) exhibited a predicted occupancy rate of 0.48, confined to specific areas, influenced by slope, habitat fragmentation diversity affecting detection rates, and the ratio of open forests impacting occupancy. Water deer (Hydropotes inermis) displayed a very low occupancy rate of 0.06 along the Tumen River Basin, with higher occupancy in lower altitude areas and increased detection in locations with high spatial heterogeneity in aspects. This study confirmed that the Mijiang area serves as a habitat supporting diverse mammals in the lower Tumen River while also playing a crucial role in facilitating animal movement and habitat connectivity. Additionally, the occupancy prediction model developed in this study is expected to contribute to predicting mammal distribution within the disrupted Tumen River basin due to human interference and identifying and protecting potential ecological corridors in this transboundary region.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.10B
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• pp.854-861
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• 2003

In this paper, we proposed the fuzzy control algorithm for efficient buffer control about traffic that is connected in ATM networks. The proposed Fuzzy control algorithm has total traffic arrival ratio, buffer occupancy ratio and Fuzzy set to search for dynamic service rates in server. That is, is based on Fuzzy logic according to the arrival ratio of total traffic and buffer occupancy ratio that is happened and reasoning. Then, made reasoning result control service rates in server about traffic that is connected with defuzzification value. Performance analysis result: it was confirmed that with the proposed scheme, performance improves at cell loss rate, when compared with the existing PBS scheme.

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.151-158
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• 2009

This study deals with the rear-end collisions in the rural aiea. The objectives of this study are 1) to analyze the characteristics of rear-end accidents of signalized intersections, and 2) to develop the accident models for Cheongju-Cheongwon. In pursing the above, this study gives the particular attentions to comparing the characters of urban and rural area. In this study, the dependent variables are the number of accidents and value of EPDO(equivalent property damage only), and independent variables are the traffic volumes and geometric elements. The main results analyzed are the followings. First, the statistical analyses show that the Poisson accident model using the number of accident as a dependant variable are statistically significant and the negative binomial accident model using the value of EPDO are statistically significant. Second, the independent variables of Poisson model are analyzed to be the ratio of high-occupancy vehicles, total traffic volume and the sum of exit/entry, and those of negative binomial regression are the main road width, total traffic volume and the ratio of high-occupancy vehicles. Finally, the specific independent variables to the rural area are the main road width, the ratio of high occupancy vehicle, and the sum exit/entry.

• Journal of the Korean housing association
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• v.23 no.2
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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.

• Korea Journal of Hospital Management
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• v.9 no.2
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• pp.102-127
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• 2004

The objective of this study is to analyze a current trend of and relating factors on profitability of the Korean Public Corporation Medical Centers(KPCMCs, hereinafter, hospitals) in Korea. There are 34 hospitals in Korea as of 2004. Among these hospitals some are red ink hospitals, others are black inks in terms of profitability. Data were collected by Korea Health Industry Development Institute(KHIDI) Statistics for Hospital Management 2000-2002 and Ministry of Health and Welfare(MOHW) financial data of public hospitals which was planned to coordinate public health care services roadmap in the long run. The samples are 32 hospitals. Profitability was measured in the aspect of profit rate with normal profit to total assets, and normal profit to gross revenues as dependent variables in respective. Independent variables were classified by general factors, i.e., location, intern/resident training, period of opening, number of beds, and managerial factors(current ratio, fixed ratio, liability to total assets, total assets turnover, personnel costs, materials cost, administrative cost), and finally factors related to patient treatment(average length of stay, bed occupancy rate, admission ratio of outpatients). The methods of analysis are correlation and multiple regression analysis. This study shows firstly, a lot of hospitals are optimal current ratio. Hospitals in upper 100% current ratio are 81.2%. And the personnel cost in total costs are high. Secondly, the trend of normal profit to gross revenues of hospitals are deteriorating gradually. And lastly, as a result of multiple regression analysis, the factors had on significant effect on normal profit to total assets are fixed ratio(+), liability to total assets(-), bed occupancy rate(+), admissions of outpatients(+), etc. And the factors had on significant effect on normal profit to gross revenues are current ration(+), fixed ratio(+), personnel cost(-), administrative expenses(-), admissions of outpatients(+), etc. In conclusion, to improve the profitability of hospitals, the efforts to reduce personnel cost and average length of stay might be needed. And also beds utilization rate need to be increased.

• Journal of Korea Port Economic Association
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• v.32 no.2
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• pp.137-156
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• 2016

This study analyzes the optimal service levels of exclusive container terminals in terms of the optimal berth occupancy rate and the ships' waiting ratios, based on the number of berths. We develop a simulation model using berth throughput data from pier P, Busan New Port, a representative port in Korea, and apply the simulation results to different numbers of berths. In addition to the above results, we analyze the financial data and costs of delayed ships and delayed cargoes for the past three years from the viewpoints of the terminal operation company (TOC), shipping companies, and shippers to identify the optimal service level for berth occupancy rates that generate the highest net profit. The results show that the optimal levels in the container terminal are a 63.4% berth occupancy rate and 10.6% ship waiting ratio in berth 4,66.0% and 9.6% in berth 5, and 69.0% and 8.5% in berth 6. However, the results of the 2013 study by the Ministry of Maritime Affairs and Fisheries showed significantly different optimal service levels: a 57.1% berth occupancy rate and 7.4% ship waiting ratio in berth 4; 63.4% and 6.6% in berth 5; and 66.6% and 5.6% in berth 6. This suggests that optimal service level could change depending on when the analysis is performed. In other words, factors affecting the optimal service levels include exchange rates, revenue, cost per TEU, inventory cost per TEU, and the oil price. Thus, optimal service levels can never be fixed. Therefore, the optimal service levels for container terminals need to be able to change relatively quickly, depending on factors such as fluctuations in the economy, the oil price, and exchange rates.

• Korea Journal of Hospital Management
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• v.14 no.2
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• pp.1-20
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• 2009

The purpose of this study is to find the determinant variables to make profitability in regional public hospitals. The data come from financial statements and annual reports of 34 regional public hospitals for five years (from year 2003 to year 2007). The T or F-test and hierarchical multiple regression analysis are used. The dependant variables are the profitability indicators, ordinary income to total asset and operating margin to gross revenue, and the independent variables are general characteristics, diagnosis and treatment patterns, financial and public benefits. The findings of this study are summarized as follows. First, Variables affecting the profitability indexes revealed from DEA results is the bed occupancy rate, number of hospitalized patients to outpatients, ratio of first medical examination for outpatients, number of daily patients per medical specialist, labor cost per patient and managerial expenses per patient. Second, the ordinary income to total asset representing the asset usage performance is affected by the average hospitalized days, bed occupancy rate, labor cost per patient and ratio of patients with medical insurance coverage. Third, the operating martin to gross revenue obtained from the actual operations of hospitals has its significance with the bed occupancy rate, number of hospitalized patients to outpatients, managerial expenses per patient and public benefit indicator. This study has some restriction not to use pannel data analysis, although it used data for five years. Accordingly, various additional studies should be done to supplement such problems.

• Journal of the military operations research society of Korea
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• v.35 no.1
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• pp.1-19
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• 2009

This study aims to improve methodology for a Defense Simulation which is to calculate wartime stockpile requirement of artillery munitions for K-9 against armored vehicles. Due to incorrect data input and distortion in simulation logic, the expected occupancy ratio for each weapon system obtained from applying a traditional method using an analytical Defense Simulation shows considerable discrepancies from what we expect from a war in the future. This study analyzes causes for incorrect data input and phenomena of distortion in simulation logic. By taking measures to control these phenomena, the study aims to present trustworthy methodology for a Hybrid Defense Simulation which is to calculate wartime stockpile requirement of munitions for ground forces by interaction between a controlled training Defense Simulation model and a analytical Defense Simulation model