• Korean Journal of Computational Design and Engineering
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• v.11 no.6
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• pp.455-463
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• 2006

Hidden line removal(HLR) algorithms can be devised either in the image space or in the object space. This paper describes a hidden line removal algorithm in the object space specifically for the CAD viewer data. The approach is based on the Appel's 'Quantitative Invisibility' algorithm and fundamental concept of 'back face culling'. Input data considered in this algorithm can be distinguished from those considered for HLR algorithm in general. The original QI algorithm can be applied for the polyhedron models. During preprocessing step of our proposed algorithm, the self intersecting surfaces in the view direction are divided along the silhouette curves so that the QI algorithm can be applied. By this way the algorithm can be used for any triangulated freeform surfaces. A major advantage of this algorithm is the applicability to general CAD models and surface-based visualization data.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.157-159
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• 2001

최근 이동 단말 사용자의 수가 급증함에 따라 네트워크 트래픽을 줄여 신속한 호 설정을 가능하게 하는 것이 중요하게 되었다. 이러한 목적을 달성하기 위하여, 빈번하게 호 요청을 하는 이동 단말들에 대해서는 캐쉬를 사용하는 기법이 제안되었다. 그러나, 기존의 캐쉬 기법은 낮은 캐쉬 실패와, 캐쉬 실패 발생시 불필요한 네트워크 지연을 초래하는 문제점이 있다. 본 논문에서는 이동 단말 사용자들이 이동 지역성을 가진다는 점을 이용하여 캐쉬 실패가 발생하더라도 HLR까지 질의하지 않고 포워딩 포인터를 따라 인접 VLR들을 질의하게 함으로써 시스템 전반적으로 위치 질의 비용을 줄여 신속한 호 설정을 가능하게 한다. 이는 HLR로 집중되는 네트워크 트래픽을 감소시켜 PCS 네트워크 사용자들에게 보다 나은 QoS를 제공하는데 이용될 수 있다. 아울러 제안하는 기법이 기존의 위치 관리 기법들보다 위치 관리비용 측면에서 보다 효율적임을 수학적 성능 분석 모델을 통하여 보인다.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.2
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• pp.244-249
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• 2004

The effects of supplemental betaine ($Betafin^{(R)}$) in the drinking water (50 g/kg) (WB) or feed (100 g/kg) (FB) were investigated on male broiler chickens ($Cobb{\times}Cobb$) exposed to 4 h episodes of heat stress at $34{\pm}1^{\circ}C$ on day (d) 35 and $36{\pm}1^{\circ}C$ from d 36 to 41. Prior to (d 1 to 34) and following heat exposure (d 35 to 41), betaine supplementation had no significant effect on body weight, total feed intake and cumulative feed conversion ratios of broilers. The total water intake of WB chicks was lower compared to controls. Prior to heat exposure, there was no difference in percentage of mortality among the three dietary groups. Following the heat challenge period, although higher percentage of control chicks succumbed to the heat challenge as compared to those of WB, it was not significantly different. The WB and FB chicks were less hyperthermic than controls in response to the heat challenge. Irrespective of treatment groups, the heat treatment resulted in a marked elevation in heterophil/lymphocyte ratios (HLR). The WB birds, however, had smaller increase in HLR than those of controls during heat exposure. Antibody production against Newcastle disease vaccine on day 35 was not affected by betaine supplementation. On d 42, WB birds had higher antibody production than those of FB. It is concluded that the WB treatment, as measured by HLR, antibody production and mortality rate, has advantages over the FB group under heat stress conditions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7A
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• pp.1064-1073
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• 1999

In the integrated systems of wired and wireless networks, it is not fit to separate cellular networks to intelligent networks so IMT-2000 is basically developed including the intelligent networks. But it is not yet determined how functional entities of IMT-2000 map the corresponding physical entities. In this paper, we propose the integrated model by mapping various functional entities of IMT-2000 into the corresponding physical entities. Also, we proposs the call model for the mobile call setup and IN service call. Based on the proposed model, we evaluate the performance and compare with IMT-2000 in terms of the mean service delay and processing delay at each physical entities.

• The Journal of Information Technology
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• v.5 no.4
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• pp.165-171
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• 2002

We propose Dynamic Circle Location Register (DCLR) scheme where each visiting location register (VLR) has a given fixed circle registration area around itself and has IDs of other VLRs in this circle area. Whenever a terminal moves to another registration area (RA), system computes whether the terminal is located in the current DCLR area and sends the recent location information of terminal to the old or new DCLR according to computing results. Also, according to change DCLR circle dynamically, we can track terminal location by querying DCLR of the current terminal when a call originates. The our scheme solves the HLR bottleneck due to the terminals frequent RA crossings and distributes the registration traffic to each of the local signaling transfer point (LSTP) area in wireless communications (WC)

• Journal of Information Processing Systems
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• v.13 no.1
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• pp.152-173
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• 2017

Mobile phones are the most common communication devices in history. For this reason, the number of mobile subscribers will increase dramatically in the future. Therefore, the determining the location of a mobile station will become more and more difficult. The mobile station must be authenticated to inform the network of its current location even when the user switches it on or when its location is changed. The most basic weakness in the GSM authentication protocol is the unilateral authentication process where the customer is verified by the system, yet the system is not confirmed by the customer. This creates numerous security issues, including powerlessness against man-in-the-middle attacks, vast bandwidth consumption between VLR and HLR, storage space overhead in VLR, and computation costs in VLR and HLR. In this paper, we propose a secure authentication mechanism based new mobility management method to improve the location management in the GSM network, which suffers from a lot off drawbacks, such as transmission cost and database overload. Numerical analysis is done for both conventional and modified versions and compared together. The numerical results show that our protocol scheme is more secure and that it reduces mobility management costs the most in the GSM network.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.453-456
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• 2000

This paper describes IMT-2000 Testbed System which consists of ATM based IMT-2000 exchange(A-lMX), RNC simulator, HLR simulator, SCP simulator, B-ISDN subscriber simulator and MS simulator. Simulators were developed to verify the mobile functions and basic services of IMT-2000 like Videophone, VoD(Video on Demand), and Internet access. UPT(Universal Personal Telecommunication) service could be adapted well to this testbed system. Until the entire network elements are developed fully, this testbed system can be used to prove new services in IMT-2000 network.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.249-251
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• 1998

본 논문은 개인 휴대통신망네에서의 각 노드간 시그날링 트래픽을 감소시키기 위한 기법에 관한 연구이다. 미래의 개인휴대통신망에서는 셀 크기가 더욱 작이지고 사용자가 증가혀 현 개인휴대통신의 문제점인 HLR로의 시그날 병목현상. 인접지역에서의 핑퐁효과 발생이 더욱 심화돌 것이다. 본 논문에서는 이와 같은 문제의 해결을 위해 각 VLR들이 자신을 중심으로 일정한 Circle Registration area를 가지면 이 area내의 VLR 들의 id를 가지는 DCLR(Dynamic Circle Location Register)이 되도록 한다. 단말이 다른 지역으로이동할 때 마다 단말이 현 DCLR area에 있는지를 검사후 해당 DCLR 로 단말의 최신 위치정보를 연속적으로 전송하고, 또한 이러한 이동에 따라 동적으로 단말의 DCLR이 변화되며, 호 발생시는 단말의 해당 DCLR을 조회함으로써 수신자의 위치를 추적한다. 이 방식은 기존 방식에서 사용자가 다른 지역으로 이동할 때마다 HLR로 매번 등록하고 질의함으로써 발생되는 HLR로의 시그널링 신호 과부하를 효율적으로 분산, 감소시키며 인접지역 경계간에 발생되는 핑퐁효과가 발생되지 않도록 한다.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.113-116
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• 2003

Mobile communication network because information through radio channel is passed, information may be eavesdropped and need information security countermeasure in communication network dimension for safe information exchange because there is possibility that is manufactured. This paper used Public Key Cryptography for protection and authentication connected with user authentication. Use public key and private key that is asymmetry encryption key to quote that is used at encryption, decryption of Public key. Encrypt IMSI and authentication message that is transmitted MS, VLR and HLR interval to public key, wish to embody transmitted authentication protocol safety.

• The Transactions of the Korea Information Processing Society
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• v.7 no.4
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• pp.1279-1289
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• 2000

Recently, research activities for combining portable computer technology and wireless communication technology are in progress to realize mobile computing environment that designed to support mobile hosts in the existing network environments. For PCN environments, the location management strategies are particularly emphasized among various strategies necessary for the mobile computing environment. Location management strategy for PCN environment, which is mostly based on the IS-41 standards brings an issue that additional network traffics are generated to deliver updata messages to home location server whenever a mobile host changes its location server. In this paper, we propose an innovative updata strategy and a search strategy that resolves the problem shown in the IS-41 scheme for HLR/VLR structure of CDMA environments. Also, this paper presents the performance comparison of proposed scheme and scheme used in IS-41 obtained from a simulation. The simulation was conducted based on the number of messages, the rate of database accesses, and the number of hops visited when the location management scheme is executed.