• 제어로봇시스템학회논문지
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• 제10권11호
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• pp.1052-1057
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• 2004

Bluetooth technology is essentially a method for wireless connectivity of a diverse set of devices ranging from PDAs, mobile phone, notebook computers, to another equipments, The bluetooth system both point-to point connection and point-to multipoint connection. In point-to multipoint connection, the channel is shared among several bluetooth devices. Two or more devices sharing the same channel form a piconet. There one master device and up to seven active slave devices in a piconet. The radio operates in the unlicensed 2.45GHz ISM band. This allows users who travel world-wide to use bluetooth equipments anywhere. Since the link is based on frequency-hop spread spectrum, multiple channels can exist at the same time. The bluetooth standard ha s been suggested that bluetooth equipments can be used in the short-range, maximum 100 meters. It has been defined that the time takes to setup and establish a bluetooth connection among devices is 10 seconds. It is a long time and may be a cause to lose a chance of finding other non-fixed devices. We propose a routing protocols for scatternets which can be used to control a mobile units(MUs) in this network. The proposed routing protocol is composed of two kinds of bluetooth information, access point(AP) and MU.

• 한국통신학회논문지
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• 제32권7B호
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• pp.431-437
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• 2007

웹 프록시 캐슁은 원하는 데이터를 접근하기 위한 지연시간과 요구하는 통신망의 대역폭을 줄이는데 효과적인 방법을 제공한다. 특히 프리픽스 캐슁은 비디오 WAN에서 비디오 전송을 위한 대안으로서 간주되는데 이는 비디오 데이터는 그 양이 너무 커서 데이터 전체를 캐쉬에 저장하는데 문제를 야기시키기 때문이다. 또한 최근의 많은 연구결과에 의하면 사용자가 인식하는 지연시간은 데이터를 전송하는 전송시간에 의해 영향을 받는 것이 아니라 TCP 연결설정 시간과 같이 데이터 전송단계를 선행하는 설정과정에 의해 많은 영향을 받는다는 것이다. 본 논문은 프록시 캐슁에서 사용되는 TCP pre-connecting 기법을 제안하며 이 기법이 TCP splicing에서 효율적으로 사용될 수 있다는 것을 보인다. 아울러 제시된 수치적인 모델은 start-up 지연시간을 줄일 수 있음을 보인다. 제안된 기법은 어떠한 프로토콜 수정이나 다른 엔티티와의 동작을 요구하지 않는다.

• 정보처리학회논문지A
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• 제12A권5호
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• pp.427-432
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• 2005

웹 클러스터 시스템에서 사용자들의 접속 요구를 효율적으로 real 서버에 분산시키기 위하여 기존의 부하분산 알고리즘들과 현재 많이 사용중인 WLC(Weighted Least Connection) 알고리즘에 대하여 연구하였다. 이 부하분산 알고리즘들은 서버들의 부정확한 부하상태 파악과 파악 시점에 문제가 있어 서버들 간에 부하 불균형이 발생함으로써 효율성이 저하된다. 본 연구에서는 사용자의 접속 요청 시 broadcasting RPC(Remote Procedure Call)를 이용하여 서버들의 다양한 부하상태를 실시간으로 파악하여 부하를 분산하는 알고리즘을 제안하고, prototype을 구현하여 성능을 실험하였다. 실험 결과, real 서버 간 부하 불균형 현상이 기존 방법에 비하여 크게 향상되었고, 응답시간이 단축되는 효과로 웹 클러스터 시스템의 성능이 향상되었다.

• 한국경영과학회지
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• 제27권1호
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• pp.33-51
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• 2002

A fully connected Artificial Neural Network (ANN) contains many connections. Compared to the pruned ANN with fewer connections, the fully connected ANN takes longer time to produce solutions end may not provide appropriate solutions to new unseen date. Therefore, by reducing the sloe of ANN, we can overcome the overfitting problem and increase the computing speed. In this research, we reduced the size of ANN by destroying the connections. In other words, we investigated the performance change of the reduced ANN by systematically destroying the connections. Then we found the acceptable level of connection-destruction on which the resulting ANN Performs as well as the original fully connected ANN. In the previous researches on the sloe reduction of ANN, the reduced ANN had to be retrained every time some connections were eliminated. Therefore, It tool lolly time to obtain the reduced ANN. In this research, however, we provide the acceptable level of connection-destruction according to the size of the fully connected ANN. Therefore, by applying the acceptable level of connection-destruction to the fully connected ANN without any retraining, the reduced ANN can be obtained efficiently.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2005년도 하계학술대회
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• pp.174-179
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• 2005

In the SONET/SDH based ASON, one VC3 connection contains 21 VC12 calls. Hence, it can serve up to 21 VC12 calls. When a new VC12 call arrives, if there exists at least one available VC3 connection in the network, that VC12 call is severed immediately. However, if there is no available VC3 connection, that VC12 call has to wait a certain time, called setup latency, for the a new VC3 connection to be established. This is inconvenient for the customers. On the other hand, if there are more VC3 connections than the network requires, this can waste network resources. In this paper, we proposed the solution for these problems. In order to reduce the number of VC12 calls which have to wait, we setup a new VC3 before all VC12 time slots are occupied. Furthermore, to avoid the waste of the network resources, we do not establish all VC3 connections at the same time, but do establish step by step.

• 한국도로학회논문집
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• 제15권6호
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• pp.49-60
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• 2013

PURPOSES : The evaluation of the pavement condition of the asphalt concrete pavement of No. 2 runway of Inchon International Airport through PMS, a supporting system for making a decision of pavement, maintenance and repair, was made, and the proper time for repair according to the PCI reduction rate was suggested. METHODS : By comparing and analyzing the evaluation results of pavements built in 2009, 2010, 2011, PCI change in each facility (No. 2 runway, C parallel taxiway, connection taxiway) was calculated. By applying the calculated change to PCI deduction rate model, the pavement condition of the target sections was estimated, and then the necessary section and time for repair were chosen. RESULTS : After careful consideration of the time for pavement and maintenance, based on the result of PCI prediction, it was estimated that the southern takeoff and landing section of No. 2 runway was required to be repaired in 2012; connection taxiway in 2013; and C parallel taxiway in 2014; however, the section which is the main moving route of connection taxiway and C parallel taxiway was needed to be repaired in 2012. CONCLUSIONS : For maintenance and repair of airport pavements, the optimal alternative should be chosen by considering economics and operability, via examining the time for repair and the aspect of management all together on the basis of this study.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2151-2154
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• 2003

Internet is deeply rooted in everyday life and many things are performed using internet in real-world, therefore internet users increased because of convenience. Also internet accident is on the increase rapidly. The security vendor developed security system to protect network and system from intruder. Many hackings can be prevented and detected by using these security solutions. However, the new hacking methods and tools that can detour or defeat these solutions have been emerging and even script kids using these methods and tools can easily hack the systems. In consequence, system has gone through various difficulties. So, Necessity of intruder trace-back technology is increased gradually. Trace-back technology is tracing back a malicious hacker to his real location. trace-back technology is largely divided into TCP connection trace-back and IP packet trace-back to trace spoofed IP of form denial-of-service attacks. TCP connection trace-back technology that autonomously traces back the real location of hacker who attacks system using stepping stone at real time. In this paper, We will describe watermark trace-back system using TCP hijacking technique to supplement difficult problem of connection maintenance happened at watermark insertion. Through proposed result, we may search attacker's real location which attempt attack through multiple connection by real time.

• 인터넷정보학회논문지
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• 제6권2호
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• pp.13-24
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• 2005

컴포넌트 조합을 통한 소프트웨어 개발은 Time-To-Market을 위한 시대적인 흐름이며 소프트웨어의 짧은 생명주기(Lifecycle) 를 극복할 수 있는 방안이다. 그러므로 효과적으로 컴포넌트를 통합하기 위한 기법들이 연구되어 왔다. 그러나 체계적이고 실용적인 기법들의 연구가 미흡하였다. 컴포넌트 통합을 위한 핵심 중에 하나는 통합을 위한 스펙을 어떻게 정의하느냐와 그 통합 스펙을 운영하기 위한 컴포넌트 아키텍쳐를 어떻게 구성하느냐 이다. 본 논문은 특화가 가능한 복합 컴포넌트를 개발하기 위해 컴포넌트 아키텍쳐를 기반으로 컴포넌트간의 조합을 위한 가변성 설계 기법을 제안하며 가변성 중에 컴포넌트간의 메시지의 흐름인 워크플로우(Workflow)에 대한 가변성 설계 기법을 제안한다. 본 기법은 컴포넌트 아키텍쳐 기반의 연결 계약(Connection Contract)을 설계하는 것이 핵심이다. 연결 계약은 컴포넌트의 제공 인터페이스(Provided Interface)를 사용하여 설계하며 이 연결 계약에 의해 동적으로 컴포넌트를 조합하고 특화(Customiztion)할 수 있는 기법을 제공한다.

• Steel and Composite Structures
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• 제32권6호
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• pp.769-778
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• 2019

The specially prefabricated steel moment connections with pyramid head is one of the significant innovations in the steel structures forms to improve the installation time and simplify the construction procedure. The beams in this structure form are supported by two top and bottom angles and web double angles. Such a configuration despite its advantages increases the welding operation and filed installation time and costs. In this paper, the effect of using beams with channel and I section in three classes of seismically compact, seismically non-compact, and slender section according to width-to-thickness ratio on the behavior of the connection was investigated under monotonic and cyclic loading. Modeling was performed by ABAQUS and verified by the results of an experimental specimen. The findings indicated that using I and channel section instead of angle section reduces the amount of welding materials as well as easing the installation procedure. However, it has no significant effect on the ultimate strength and ductility of the connection. Furthermore, if the beam section is seismically compact, this form is considered as a special moment frame that has a rotation capacity up to 0.04 radians without any reduction in connection moment resistance.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권3호
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• pp.243-247
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• 2005

The Different-volume- V-connection transformer is known as an electric power source that can supply 3-phase electric power and single-phase electric power at the same time. Usually, we use two single-phase transformers that have different volumes. In this paper, we propose the use of a 3-phase 5-leg transformer with the different-volume- V-connection. And, we examine the magnetic properties of the 5-leg core model with the different-volume- V-connection. The magnetic properties of cores with the different-volume- V-connection are compared with those with the delta-connection. In order to express the magnetic anisotropy of the core materials and to calculate the iron loss directly, the two-dimensional vector magnetic property is considered with the E&SS modeling in the simulation.