• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.5
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• pp.995-1003
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• 2004

A number of Internet application services are used with the development of Internet backbone nowadays. Well-known services such as WWW, ]n, email are provided at first time. Tremendous unwell-known services are presented according to the demands of various contents. After analyzing PDU information of the packet using unwell-known port travelling on the internet, searching internet service type and its statistical data is provided with internet traffic analyst as very useful information. This paper presents the mechanism to extract the internet application services operated on (un)well-known port of UDP or TCP used occasionally through netflow and tcpdump method introduced by ethereal and the operation scheme of the service. Afterwards to get the detailed statistics of the analyzed application service, the agent and the server environment, the agent gathering raw data traffics and the server adapting the traffic received from the agent BNF(Backus-Naur Form) method, is also introduced. Adapting the presented mechanism eve. LAN of Andong national university, the internet traffic service type and the detailed statistics of the analyzed application services which provides with internet traffic analyst are presented as very useful information.

• Journal of Korea Port Economic Association
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• v.21 no.1
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• pp.73-91
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• 2005

The goal of the project on developing Korea as the logistics hub of Northeast Asia is to develop Busan Port and Gwangyang Port as international logistics centers by promoting and attracting more warehouses. As is well known, there is intense competition among ports located in major economic blocs to become the regional logistics hub. Gwangyang is second to none in terms of being favorably located at the center of Northeast Asia. Gwangyang Port, however, lacked in SOC construction and faced the poor government support politics hub of Northeast Asia. They are i) expanding the logistics infrastructuressuch as expressway and railroads between Yeosu Airport and Gwangyang Port, ii) Setting up new port hinterland and industrial complex in the vicinity of Gwangyang Port iii) securing high value-added fixed cargo traffic, and iv) improving laws and institutions.

• The Journal of the Korea Contents Association
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• v.5 no.5
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• pp.172-181
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• 2005

The latest attack type against network traffic appeared by worm and bot that are advanced in DDoS. It is difficult to detect them because they are diversified, intelligent, concealed and automated. The exisiting traffic analysis method using SNMP has a vulnerable problem; it considers normal P2P and other application program to be harmful traffic. It also has limitation that does not analyze advanced programs such as worm and bot to harmful traffic. Therefore, we analyzed harmful traffic out Protocol and Port analysis. We also classified traffic by protocol, well-known port, P2P port, existing attack port, and specification port, apply singularity weight to detect, and analyze attack availability. As a result of simulation, it is proved that it can effectively detect P2P application, worm, bot, and DDoS attack.

• Journal of Korea Port Economic Association
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• v.38 no.4
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• pp.1-11
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• 2022

Although the port distripark concept and its development policy have been introduced since almost twenty years, there is no visible results of the policy. Specifically, the level of value-added logistics using transhipment cargo is too low. In this paper, we mainly focus on the causes of the policy failure of port distripark's value added activities in terms of conceptual as well as practical or functional. Definitely, the study reviews the concept of port distripark compared to industrial park or bonded factory. The study also analyzes the differentiation of port distripark and port hinterland. The study generats that the problem or error that may occur when port hinterland is identified with the port distripark. Last but not least, the limitations of value added logistics is generated on the study. We examined in depth whether the already well known value added activity of port distripark is really activities that add 'value'.

• Broadcasting and Media Magazine
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• v.11 no.1
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• pp.78-85
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• 2006

Cognitive radio is a paradigm for wireless communication in which either network of wireless node itself changes particular transmission or reception parameters to execute its tasks efficiently without interfering with the licensed users. This paper represents a performance of the cognitive radio technology on dual polarized MIMO system using six-port receiver. Six-port technology is well known direct conversion receiver. In this paper, a six-port phase discriminator based polarization signal separation is shown. That is, the SER(Symbol Error Rate) performance is improved using polarization separator and simple receiver architecture is proposed applying six-port receiver. The six-port technology has priority to adapt changeable frequency system and variable environments for cognitive radio. In general, dual polarized MIMO system has good capacity and quality using polarization separator [1].

• Journal of Power Electronics
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• v.17 no.6
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• pp.1433-1444
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• 2017

A family of non-isolated DC-DC three-port converters (TPCs) that allows for a more flexible power flow among a renewable energy source, an energy storage device and a current-reversible DC bus is introduced. Most of the reported non-isolated topologies in this area consider only a power consuming load. However, for applications such as hybrid-electric vehicle braking systems and DC microgrids, the load power generating capability should also be considered. The proposed three-port family consists of one unidirectional port and two bi-directional ports. Hence, they are well-suited for photovoltaic (PV)-battery-DC bus systems from the power flow viewpoint. Three-port converters are derived by combining different commonly known power converters in an integrated manner while considering the voltage polarity, voltage levels among the ports and the overall voltage conversion ratio. The derived converter topologies are able to allow for seven different modes of operation among the sources and load. A three-port converter which integrates a boost converter with a buck converter is used as a design example. Extensions of these topologies by combining the soft-switching technique with the proposed design example are also presented. Experiment results are given to verify the proposed three-port converter family and its analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.4
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• pp.895-899
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• 2000

A method of measuring Q of a two port cavity by scattering parameters is proposed. The scattering parameters of a two port cavity resonator are derived by a lumped equivalent circuit model as a function of cavity parameters, including the cavity Q. These can be also obtained by direct measurement with a modern network analyzer, The results show good agreement with those from other well-known methods. This two port measurement can provide additional information such as the coupled power ratio, which is one of the important parameters for the beam accelerating cavities.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1292-1295
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• 2009

최근 인터넷 사용량이 급증함으로 인해 인터넷 응용프로그램의 개발, 종류 및 사용이 기하급수적으로 늘어나고 있다. 초기에 사용되었던 웹, 파일전송, E-mail 등 well-known port 기반 서비스가 변화되어 unwell-known port 기반 서비스가 주를 이루고 있다. 이러한 상황에서 효율적인 네트워크 관리를 위한 응용 트래픽의 분류가 어려워지고 있으며, 효과적인 트래픽 분류를 위한 연구가 많이 진행되고 있다. 본 논문에서는 가장 많이 사용되는 인터넷 응용프로그램인 웹하드를 대상으로 이들로부터 발생하는 트래픽을 분석하였다. 먼저 웹하드의 정의 및 기능과 그 종류에 대해서 기술하였다. 또한, signature 기반 분류 방법으로 웹하드 트래픽을 패킷 캡쳐 툴과 Flow 을 이용하여 분석하고 그 결과로부터 응용 트래픽 분류의 관점에서의 웹하드 트래픽의 특징에 대해서 기술하였다.

• Journal of Navigation and Port Research
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• v.33 no.7
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• pp.477-482
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• 2009

In this paper the order picking problem in warehouses is considered, a topic which has received considerable attention from the international academic body in recent years. The order picking problem deals with the retrieval of order items from prespecified locations in the warehouse, and its objective is usually the minimization of travel time or travel distance. Hence, a well-thought order picking policy in combination with an appropriate storage policy will enhance warehouse efficiency and reduce operational costs. This paper starts with a literature overview summarizing approaches to routing order pickers, assigning stock-keeping units to pick locations and designing warehouse layouts. Since the layout design might affect both storage and routing policies, the three factors are interdependent with respect to order picking performance. To test these interdependencies, a simulation experiment was set up, involving two types of warehouse layout, four types of storage policy, five well-known heuristics and five sizes of order picking list. Our results illustrate that from the point of view of order picking distance minimization it is recommended to equip the warehouse with a third cross aisle, although this comes at the cost of a certain space loss. Additionally, we propose a set of most appropriate matches between order picking heuristics and storage policies. Finally, we give some directions for further research and recommend an integrated approach involving all factors that affect warehouse efficiency.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.6
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• pp.38-45
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• 2004

This paper studies the effects of intake port configuration on the swirl that is key parameter in the flow field of direct injection diesel engines. In-cylinder flow characteristics is known to have significant effects on fuel air mixing, combustion and emissions. To investigate the swirl flow generated by various intake ports, steady state flow tests were conducted to evaluate the swirl. Helical port geometry, SCV shape and bypass were selected as the design parameters to increase the swirl flow and parametric study was performed to choose the optimal port shape that would generate a high swirl ratio efficiently. The results revealed that a key factor in generating a high swirl ratio was to suitably control the direction of the intake air flow passing through the valve seat. For these purposes, we changed the distance of helical and tangential port as well as installed bypass near the valve seat and the effects of intake port geometry on in-cylinder flow field were visualized by a laser sheet visualization method. From the experimental results, we found that the swirl ratio and mass flow rate had a trade off relation. In addition, the result indicates that the bypass is a effective method to increase the swirl ratio without sacrificing mass flow rate.