• Proceedings of the Korean Society of Computer Information Conference
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• 2015.07a
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• pp.1-4
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• 2015

현재 고해상도 디스플레이 제품 생산은 대량 생산 공정 시스템으로 가동하고 있으며, 대량 생산 과정에서 WAFER의 제작 불량률을 낮추는 것이 생산업체에서 무엇보다도 주요한 목표이며 이와 함께 불량 제품을 정확하고 빠르게 검출하는 것이 매우 중요하다. 본 논문에서는 불량 WAFER을 정확하게 검출하기 위한 검출시스템으로 멀티 포인트 온도 검출 방법으로 구현된 면적형 온도 센서 기능과 검출된 데이터를 유/무선 통신방식으로 상위의 관리/모니터링 시스템으로 전송 할 수 있는 기능을 가진 마스터 콘트롤러 시스템을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.05a
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• pp.78-79
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• 2018

이중화 시스템은 가용성 및 신뢰성 향상을 위한 방안의 하나로 시스템의 고장으로 인한 임무중지나 성능 감소를 방지하기 위한 시스템이다. 이중화 구조 중 하나인 마스터-슬레이브 구조를 갖는 시스템에서는 슬레이브 모듈이 마스터 모듈의 상태를 모니터링하고 있다가 이상 감지 시 슬레이브 모듈에서 마스터 모듈로 전환되는 기능을 가지고 있다. 본 논문에서는 네트워크 시스템 구성 시 항시 시스템 fail 를 감지하고 무중단 데이터 전송을 수행하기 위한 네트워크 이중화 구성 방안에 대해 소개 한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8A
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• pp.613-619
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• 2003

Bluetooth is a communication technology enabling short-range devices to be wirelessly connected. A master and one or more slave devices are connected to form a piconet, and piconets are joined to form a scatternet. The units participating in two or more piconets in a scatternet, is called bridge or gateway nodes. In order to operate the scatternet efficiently, both piconet scheduling for the master and slaves of a piconet, and scatternet scheduling for the bridge nodes are playing important roles. In this paper, we propose a traffic-adaptive dynamic scatternet scheduling algorithm based on rendezvous points and rendezvous windows. The performance of the proposed algorithm is compared and analyzed with that of a static scheduling algorithm via simulations. Simulation results show that our algorithm can distribute wireless resources efficiently to bridge nodes depending on the traffic characteristics.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.451-453
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• 2003

본 논문은 블루투스 MAC 계층에서의 패킷 스케줄링 성능의 개선을 목적으로 한다 현재 대부분의 많은 블루투스 MAC 계층 스케줄링 방식은 라운드로빈(RR)을 사용하고 있는데, 많은 슬롯과 시간을 낭비하게 되고 최적화된 업링크와 다운링크에 적합하지 않다. 한편, 블루투스의 마스터 노드에서 생기는 자원 낭비 문제를 해결하기 위한 몇 가지 MAC 스케줄링 알고리즘이 있다. 본 논문에서는 Bin-packing 과 DRR 을 이용하는 MAC 계층에서의 효과적인 패킷 스케줄링 알고리즘을 제안하고 시뮬레이션을 통해서 그 성능이 기존 방식에 비해 우월함을 보인다.

• The Journal of Korean Association of Computer Education
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• v.13 no.5
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• pp.103-110
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• 2010

If an exterior computer wants to join the Grid/cloud computing platform for a while, all of the related firewalls' filtering rule should be immediately updated. As the platform of Internet application is gradually evolving into the Grid/Cloud environment, the R&D requirement for the dynamic traversing of the multiple firewalls by a single try is also increasing. In this paper, we introduce the new mechanism for the dynamic traversing of the multiple firewalls using the concept of the one-time master key that can dynamically unlock the tiers of firewalls simultaneously instead of the existed filtering rule based method like a lock management at each firewall. The proposed master keys are like one-time password, consisted of IP addresses, port numbers, and TCP's initial sequence numbers, and generated by end users not administrators. They're exchanged mutually in advance and used to make a hole at local-side firewalls for the other's packet incoming. Therefore, the proposed mechanism can function regardless of the number or type of firewalls.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.7
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• pp.1608-1616
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• 2015

This paper describes an efficient hardware implementation of lightweight encryption algorithm LEA-128/192/256 which supports for three master key lengths of 128/192/256-bit. To achieve area-efficient and low-power implementation of LEA crypto- processor, the key scheduler block is optimized to share hardware resources for encryption/decryption key scheduling of three master key lengths. In addition, a parallel register structure and novel operating scheme for key scheduler is devised to reduce clock cycles required for key scheduling, which results in an increase of encryption/decryption speed by 20~30%. The designed LEA crypto-processor has been verified by FPGA implementation. The estimated performances according to master key lengths of 128/192/256-bit are 181/162/109 Mbps, respectively, at 113 MHz clock frequency.

• The KIPS Transactions:PartC
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• v.10C no.2
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• pp.185-190
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• 2003

Bluetooth communication is based on piconet, which is composed by one master and maximum seven slaves. Several piconets can be interconnected via an inter-piconet Bluetooth unit called a bridge unit to form a Bluetooth scatternet. This bridge node can make its presence in each piconet by switching. This switching must be carefully scheduled so that slot wastage and, hence, packet delays are minimized. In this paper, we introduce an efficient inter-piconet scheduling scheme based on sniff mode. This scheme tries to minimize the wastage of slots by having the bridge unit sniff with its peering masters with time limits and communicate with its slaves in remaining slots. The sniff time limits are determined adaptively based on the amount of traffic in each piconet. Simulation results show this scheme outperforms round-robin scheme based on sniff intervals of equal lengths.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.7
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• pp.1295-1300
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• 2001

This paper presents the system that decreases the Jitter value having an important effect for signal quality in optical disc memory. Level controller of input signal was made and applied to line between format generator and laser beam recorder of DVD. This try means to decrease jitter value without adjustment for many kinds of mastering process. Experimental results show that the jitter value is about 6.9%.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2333-2340
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• 2016

A LEA (Lightweight Encryption Algorithm) crypto-processor was designed, which supports three master key lengths of 128/ 192/256-bit, ECB and CTR modes of operation. To achieve high throughput rate, the round transformation block was designed with 128 bits datapath and a pipelined structure of 16 stages. Encryption/decryption is carried out through 12/14/16 pipelined stages according to the master key length, and each pipelined stage performs round transformation twice. The key scheduler block was optimized to share hardware resources that are required for encryption, decryption, and three master key lengths. The round keys generated by key scheduler are stored in 32 round key registers, and are repeatedly used in round transformation until master key is updated. The pipelined LEA processor was verified by FPGA implementation, and the estimated performance is about 8.3 Gbps at the maximum clock frequency of 130 MHz.

• KIPS Transactions on Computer and Communication Systems
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• v.8 no.3
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• pp.73-78
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• 2019

Due to frequent topology changes in wireless networks, inter-node link disconnection and path re-establishment occur, causing problems such as overloading control messages in the network. In this paper, to solve the problems such as link disconnection and control message overload, we perform path setup in three steps of the neighbor node discovery process, the route discovery process, and the route management process in the wireless network environment. The link stability value is calculated using the information of the routing table. Then, when the zone master monitors the calculated link value and becomes less than the threshold value, it predicts the link disconnection and performs the path reset to the corresponding transmitting and receiving node. The proposed scheme shows a performance improvement over the existing OLSR protocol in terms of data throughput, average path setup time, and data throughput depending on the speed of the mobile node as the number of mobile nodes changes.