• Journal of KIISE:Information Networking
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• v.27 no.2
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• pp.237-246
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• 2000

A broadband access network in B-ISDN subscriber network, plays a role of concentration or multiplexing of various subscribers into a service node. For call and connection control functions, DSS2 and B-ISUP signalling protocols are standardized for each of a subscriber side and a network node. B-BCC and B-ANCC protocol were proposed for VB5.2 interface. This interface allows dynamic control of ATM connections at the broadband access network. To establish an end-to-end ATM connection, interworking functions between VB5.2 interface's connection control protocol and the signalling protocol, are performed at the service node. A sequential interworking model and a parallel interworking model were proposed for these interworking functions. The sequential interworking model recommended by ITU-T causes an overall connection setup delay by introducing the access network, because this model proceeds the signalling protocol of network node after the response of VB5.2 interface protocol. On the other hand, the parallel interworking model proceeds the signalling protocol and the VB5.2 interface protocol simultaneously. The simultaneity of the parallel interworking model minimizes the overall connection setup delay. In this paper, we analyze and simulate above two interworking models with B-BCC or B-ANCC protocol in terms of a connection setup delay and completion ratio.

• Journal of Communications and Networks
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• v.12 no.5
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• pp.411-432
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• 2010

We consider three different secure broadcasting scenarios: i) Broadcast channels with common and confidential messages (BCC), ii) multi-receiver wiretap channels with public and confidential messages, and iii) compound wiretap channels. The BCC is a broadcast channel with two users, where in addition to the common message sent to both users, a private message, which needs to be kept hidden as much as possible from the other user, is sent to each user. In this model, each user treats the other user as an eavesdropper. The multi-receiver wiretap channel is a broadcast channel with two legitimate users and an external eavesdropper, where the transmitter sends a pair of public and confidential messages to each legitimate user. Although there is no secrecy concern about the public messages, the confidential messages need to be kept perfectly secret from the eavesdropper. The compound wiretap channel is a compound broadcast channel with a group of legitimate users and a group of eavesdroppers. In this model, the transmitter sends a common confidential message to the legitimate users, and this confidential message needs to be kept perfectly secret from all eavesdroppers. In this paper, we provide a survey of the existing information-theoretic results for these three forms of secure broadcasting problems, with a closer look at the Gaussian multiple-input multiple-output (MIMO) channel models. We also present the existing results for the more general discrete memoryless channel models, as they are often the first step in obtaining the capacity results for the corresponding Gaussian MIMO channel models.

• The Journal of Fisheries Business Administration
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• v.39 no.3
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• pp.49-65
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• 2008

In Korea, deep-sea fishing industry is faced with pressure of being thrown out of business, because of the upcoming unfavorable business conditions such as the fishing regulation of coastal countries, Korea-US Free Trade Agreement(KORUS FTA), and the other socio-economic changes. Hence, we present an evaluation of future business competitive for the deep-sea fishing industry so that the government can develop a concession plan for the deep-sea fishing industry by utilizing the results of this study. In efficiency analysis of deep-sea fishing industry, the decision maker may have two problems: (1) how to deal with multiple inputs and outputs of deep-sea fishing industry and (2) how to assign the weights on different inputs and outputs, In this paper, we proposed to use Data Envelopment Analysis (DEA) to estimate efficiency of deep-sea fishing industry with multiple inputs and outputs. In the DEA, The direct impact of KORUS FTA, fishing regulation of coastal countries, fishing charges, and competitive fishing conditions were used as input parameters while the profitability and secured fishing quarters, as outputs. The results of DEA-BCC model indicate that 6 out of 12 DUMs have better efficiency under variable return to scale assumption.

• Korean Business Review
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• v.17 no.2
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• pp.185-202
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• 2004

There is an increasing interest in measuring and comparing the efficiency of organization units whose operations are functionally similar and autonomous. Data Envelopment Analysis(DEA) has been extensively used to evaluate the efficiency of non-profit organizations as a whole. This study applies a modified DEA model (Input-oriented BCC model with Nondiscretionary variables) to identify the performance of local government in Korea. It is found that utilizing DEA as a mean of evaluating the performance of local governments yields useful information to decision makers trying to maintain more efficient practices.

• The Journal of the Korea Contents Association
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• v.20 no.4
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• pp.159-168
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• 2020

This study aims to utilize DEA, analyze the efficiency of Korean coffee franchises, look into the factors that affect efficiency, and improve the efficiency of Korean coffee franchises. The main results of this study are as follows. First, according to CCR model standards, there are a total of 9 efficient coffee franchises and according to BCC model standards, there are a total of 12 efficient coffee franchises. A total of three of the inefficient DMUs were found to have a value of 1 for BCC, while the other 25 were found to be inefficient for both technology and scale. Second, of 28 franchises, 11 were analyzed to be decreasing return to scale and through future increased investments of optimum levels, business performance can be improved and efficiency can be enhanced. Analysis showed that 9 franchises appeared as CRS and it is most ideal to maintain the yield of future output elements at current levels and the work efficiency of 8 franchises in increasing returns to scale states expands as production scales increase according to specialization and role division and yield can relatively improve a lot. Third, the analysis of factors affecting the efficiency of franchises through the Tobit regression analysis showed that the number of franchises and operating periods had a positive (+) effect on efficiency. Based on this study, the efficiency of coffee franchises should be analyzed to establish strategies to maximize efficiency. Based on this study, the efficiency of coffee franchises should be analyzed to establish strategies to maximize efficiency.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.145-150
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• 2020

The provision of information on the profitability and efficiency during the transition from growing rice to substitute crops is an essential task for the proliferation and settlement of the production adjustment system. First, the profitability of the soybean + barley cropping system was analyzed. The average income of the farms with the soybean + barley cropping system surveyed was 868,000 Won, with an income proportion of 55.1%. With earned income that is approximately 1.7 times higher than that of growing only rice, it is determined to be more profitable. Then, the efficiency of the farms was analyzed through DEA analysis. The efficiencies of the farms were found to include the CCR model (0.927815) and the BCC model (0.97544). It was also found that there are 10 CCR and 14 BCC results with an efficiency value of 1. With an efficiency value of more than 0.9 on average, it can be deemed as efficient management in general. In addition, by presenting a proposal for the improvement of inefficient farms, the target value was provided in order for inefficient farms to become efficient farms.

• Journal of Korea Port Economic Association
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• v.37 no.1
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• pp.19-30
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• 2021

The 21st Century Maritime Silk Road (MSR) is an important part of Belt and Road Initiative(BRI). As an economic and trade corridor for dozens of countries in Asia, Europe and Africa, and the port as an important link node, the efficiency of port operation directly affects the implementation of BRI's strategy. On the basis of combining BRI and related evaluation methods of port efficiency, this paper uses DEA-BCC model to select port production berth number and production berth length as input index container throughput and cargo throughput as output index to analyze the port efficiency of 14 ports in China. The results show that: (1) The overall efficiency level of the ports along the MSR is relatively low. Most of the ports have not reached the DEA efficiency and there are different degrees of problems in scale investment and technological improvement. However, this situation is accompanied by the implementation of China's maritime cooperation strategy and becoming better year by year. (2) The low operating efficiency of ports along China's MSR is mainly due to the lack of coordination between scale efficiency and technical efficiency, which is caused by insufficient scale investment in the port itself, weak economic linkage between the hinterland and the port, (3) Whether a port has a strong comprehensive strength does not entirely depend on the cargo throughput or scale but also includes the port's operating efficiency.

• Industry Promotion Research
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• v.8 no.4
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• pp.267-276
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• 2023

Based on the tourism input-output data of five provinces and cities in China's Bohai Rim region from 2015~2021, this study analyzes the efficiency of regional tourism using DEA-BCC and DEA-Malmquist index, as well as its contribution to regional economic efficiency, and identifies factors influencing the comprehensive efficiency. The research results indicate that the comprehensive efficiency of the tourism industry in the China Bohai Sea region has reached an optimal level of 88.9%, but there is still room for improvement, with overall fluctuations. The overall productivity of the tourism industry exhibits a "U"-shaped fluctuating pattern, with growth mainly driven by technological advancements. Due to the impact of the COVID-19 pandemic, the region experienced a nearly 50% decrease in total factor productivity in 2019~2020. However, in 2021, with the implementation of various government stimulus policies, the tourism efficiency rapidly recovered to 80% of pre-pandemic levels. In terms of the impact of the tourism industry on the regional economy in the China Bohai Sea region, Hebei Province stands out as a significant contributor. Based on the aforementioned research findings, the following recommendations are proposed in three aspects: optimizing the supply structure, increasing innovation investment, and strengthening internal collaboration. These recommendations provide valuable insights for enhancing regional tourism efficiency and promoting regional synergy.

• Journal of Korea Multimedia Society
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• v.4 no.5
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• pp.455-464
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• 2001

For future multimedia services, one of the most crucial issues is building an access network that can accommodate multimedia services in subscriber network. The VB5.2 interface of B-ISDN located between an access network and a service node allows dynamic allocation and release of ATM resources. The SG 13 of ITU-T is standardizing the B-BCC protocol, which is sequentially interworked with signaling protocols in the service node. To minimize a connection setup delay of the sequential interworking mode, we proposed the parallel interworking model in which the SN executes simultaneously the connection control protocol of VB5.2 interface and signaling protocol. We simulate two interworking models in terms of a connection setup delay and a completion ratio. The results of simulation show that our proposed parallel interworking model for the VB5.2 interface reduces the setup delay and has the similar completion ratio compared to the sequential interworking model. however, the connection setup delay of parallel interworking model becomes about seven tenths of that of the sequential interworking model and the improvement become larger as the arrival rate increased.

• Journal of Navigation and Port Research
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• v.39 no.6
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• pp.507-514
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• 2015

The purpose of this study is to analyze the efficiency of resident companies in port hinterland logistics that are currently operating. The subjects of the efficiency analysis include 13 logistics hinterland resident companies in Incheon Port and Busan Port. Investment amounts, area, and number of employees were selected as input variables, and volume and sales amounts were selected as output variables. As for the efficiency analysis methods, traditional CCR and BCC models were applied. To overcome the limits of these models, a super-efficiency model and a Super-SBM model were also applied. According to the super-efficiency model analysis, the mean was 0.777 and the standard deviation was 0.54, indicating an approximate 33% difference of efficiency among the companies. According to the Super-SBM model analysis, the mean was 0.649 and the standard deviation was 0.489. When considering residuals in the super-efficiency model, the average efficiency score among the companies decreased by approximately 13%. This means that the efficiency score decrease of DMU, where non-radial residuals exist at about 18% on average. Examining the inefficiency of the inputs, the inefficiency of the number of employees turned out to be largest at -45%, compared to 'area' at -33% and 'investment amount' at -33%.