• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.327-330
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• 2007

This article discusses a capacity planning method in QoS-guaranteed IP networks such as BcN (Broadband convergence Network). Since IP based networks have been developed to transport best-effort data traffic, the introduction of multi-service component in BcN requires fundamental modifications in capacity planning and network dimensioning. In this article, we present the key issues of the capacity planning in multi-service IP networks. To provide a foundation for network dimensioning procedure, we describe a systematic approach for classification and modeling of BcN traffic based on the QoS requirements of BcN services. We propose a capacity planning framework considering data traffic and real-time streaming traffic separately. The multi-service Erlang model, an extension of the conventional Erlang B loss model, is introduced to determine required link capacity for the call based real-time streaming traffic. The application of multi-service Erlang model can provide significant improvement in network planning due to sharing of network bandwidth among the different services.

• 대한산업공학회지
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• 제37권3호
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• pp.229-233
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• 2011

The existing approaches for analyzing the data service capacity of CDMA2000 1X EV-DO (Evolution-Data Only) systems have focused on deriving the maximum number of active customers assuming that the data rates provided to the customers can be determined beforehand. However, we have seen that through real experiment, the data rates actually provided to the customers adaptively change according to the number of active customers. In this paper, we propose new capacity analysis model considering the data rate adaptation. Numerical examples are also presented to obtain the maximum input traffic rates for various values of the length of data burst and the required mean delay bound.

• 한국컴퓨터정보학회논문지
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• 제23권11호
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• pp.59-66
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• 2018

Data Distribution Service(DDS) provides the communications service programmers need to distribute time-critical data between embedded and/or enterprise devices or nodes. In this paper, I propose efficient methods for transmitting and receiving messages of various characteristics in real-time using DDS middleware. For high-frequency characteristic data, I describe several DDS packet types and various default and extended DDS QoS policies. In particular, the batching method is probably the best solution when considering several performance aspects. For large-capacity characteristic data. I will show a method using extended DDS QoS policies, a segmentation and reassembly method, and transmitting and receiving a large-capacity data with low priority method considering network conditions. Finally, I simulate and compare the result of performance for each methods. This results will help determine efficient methods for transmitting and receiving messages of various characteristics using DDS middleware.

• 대한산업공학회지
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• 제24권2호
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• pp.241-249
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• 1998

In this paper, we seek to find an optimal allocation of link capacity in a data communication network. The architecture of the data communication network considered in the study is an online-service network based on public switched telephone network(PSTN) and packet switched data network(PSDN). In designing the architecture of the network, we need to deal with various measures of quality of service(QoS). Two important service measures are the call blocking probability in PSTN and the data transfer delay time in PSDN. Considering the tradeoff between the call blocking probability and the data transfer delay time in the network, we have developed the optimal link capacity allocation model that minimizes the total link cost, while guarantees the call blocking probability and the data transfer delay time within an acceptable level of QoS. This problem can be formulated as a non-linear integer programming model. We have solved the problem with tabu search and simulated annealing methods. In addition, we have analyzed the sensitivity of the model and provided the insight of the model along with computational results.

• 한국멀티미디어학회논문지
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• 제6권7호
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• pp.1219-1230
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• 2003

본 논문에서는 음성, 스트림-데이터 및 패킷-데이터 트래픽이 혼합된 환경에서 전체 채널을 음성 우선 채널과 음성 비우선 채널로 구분하여 공유하는 CDMA 시스템을 마르코프 체인으로 해석한다. 실시간 전송이 요구되는 음성 서비스는 음성 우선 채널에 대해서는 선점 우선권(preemptive priority)을 가지고 사용하며, 음성 비우선 채널에 대해서는 스트림-데이터 서비스와 동등한 순위를 지니고 사용한다. 지연에 다소 민감하지 않은 스트림-데이터 서비스에 대해서는 버퍼를 사용한다. 또한, 전자우편 등과 같은 패킷-페이터 서비스는 타 서비스에 의해 사용되고 있지 않는 잔여 채널을 이용하여 최선의 시도를 통해 전송하도록 한다. 본 논문에서는 채널의 선점 우선권을 지니는 음성 서비스 및 버퍼가 적용된 스트림-데이터 서비스를 2-차원 마르코프 체인으로 모델링하고 분석하였으며, 잔여 용량(residual capacity)을 기초로 하여 패킷 데이터 트래픽에 대한 수학적 분석을 수행하였다.

• 대한교통학회지
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• 제9권1호
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• pp.5-18
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• 1991

Two-Lane, two-way roads account for approximately 92% of total road length in Korea and accomplish the majority of regional transport activities. Nevertheless not too many research have been made on two-lane roads particularly efficiency related topics such as capacity and travel time studies. In this study a full scale data collection was conducted using video equippments on rural two-lane roads to determine capacity Passenger Car Equivalents(PCE) and Level of Service criterion. Various PC programs were utilized to reduce traffic data and Walker ME? and Headway Method were employed to determine PCE's for heavy vehicles. The reseach has shown that capacity and PCE's for two-land two-way roads in Korea are 3200 pcph and 1.1∼1.9 resectively. In addition percent time delay was used as the basis of developing Level of service criterion on two-lane roads in Korea.

• 복합신소재구조학회 논문집
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• 제1권1호
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• pp.34-45
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• 2010

This paper describes the design, manufacturing process, testing, application, and assessment of capacity-ratings of the first all advanced composites bridge on a public highway system. In order to verify the bridge design prior to the field application, a sub-scale bridge superstructure was built and tested in the laboratory. The field load test results were compared with those of the finite element analysis for the verification of validity. To investigate its in-service performance, field load testing and visual inspections were conducted under an actual service environment. The paper includes the presentation and discussion for advanced composites bridge capacity rating based on the stress modification coefficients obtained from the test results. The test result indicates that the advanced composites bridge has no structural problems and is structurally performing well in-service as expected. Since these composite materials are new to bridge applications, reliable data is not available for their in-service performance. The results may provide a baseline data for future field advanced composites bridge capacity rating assessments and also serve as part of a long-term performance of advanced composites bridge.

• 지식경영연구
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• 제11권1호
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• pp.97-113
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• 2010

Given the large investment and prevalence of knowledge management (KM) in organizations, it has become important to analyze the effects of KM activities on organizational performances. A theoretical framework is proposed to investigate the impact of KM activities on innovation capabilities in the IT service industry. This study considers KM activities as the major determinant that enhances absorptive capacity. KM activities enhance employees'ability to obtain external knowledge, resulting in increasing intellectual capital. Thus, this study proposes that absorptive capacity plays a mediating role between KM activities and innovation capability. Additionally, this study investigates the key antecedents of KM activities that promote employees' knowledge sharing. Based on prior studies on KM, this study posits KM team activities and top manager support as KM activities. The proposed research model was tested by using survey data collected from 556 employees in the IT service industry. PLS (partial least squares) was employed for the analysis of the data. The findings of this study showed that KM activities and absorptive capabilities play a significant role in enhancing service innovation and process innovation in the IT service industry. The results also shed light on the mediating role of absorptive capacity between KM activities and innovation capability. Moreover, both KM team activities and top manager support serve as the salient antecedents of promoting employees' knowledge sharing.

• Journal of Information Technology Applications and Management
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• 제20권1호
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• pp.173-195
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• 2013

This study is to analyze the impact of the absorptive capacity and information technology (IT) on firms' innovation. The absorptive capacity is measured by R&D investment intensity, R&D manpower concentration, and the firm's size. We try to see the interaction effects between the absorptive capacity and IT usage on firms' innovation. We also look into the differences of the impacts between manufacturing industry and service industry as well as IT industry and service industry. We found that IT and R&D intensity have stronger interaction effect on innovation in manufacturing industry than in service industry, which shows that IT plays a more important role in the accumulation of knowledge in R&D activity in manufacturing industry. Contrarily, in service industry, IT and R&D manpower concentration has significant interaction effects on innovation. This means that the role of IT in service industry is sharing knowledge and experiences among employees in service industry. The interaction effect between firm's size and IT has positive impact on innovation in manufacturing industry, while it has negative impact on innovation in service industry. Finally, we found that the interaction effect is statistically significant in non-IT industry, while it is not statistically significant in IT industry.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.117-120
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• 2000

This paper discusses solutions for forward link power allocation based on 3GPP(FDD) standardization reports and which meet the required Eb/No of forward link channels. In addition, the forward link user capacity in a mixed service environment. Cell coverage is induced from the user capacity solutions using the urban propagation model. In an urban macrocell environment, the forward link user capacity turns out to be roughly 29 and 3, respectively, for voice and data service (144 kbps) at a distance of 1 km, and in an urban microcell environment, the user capacity turns out to be Toughly 14, 4, and 2, respectively, for voice and two data services (144 kbps, 384 kbps) when the cell radius is 0.2 km.