• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.12
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• pp.2635-2643
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• 1997

In this paepr, a routing algorithm is proposed in order to reduce average end-to-end delay and congesting in the high speed network. The algorithm proposed here uses the existing one which adaptively modifies routes and the amount of traffic allocated to each link as user traffic partterns flutuate. This algorithm is ELB(Equitable Load Balancing). Also, the new algorithm considers the proportional to the distance between source and destination. It reduces congestion from the ELB and average end-to-end delay from the propagation dealy concepts respectively. Through the simulation, it shows that the algorithm proposed here reduces average end-to-end delay over low load to high load, and it also guarantees the congestion control.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.1-3
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• 2004

이 논문에서는 기존의 계층 링을 수정한 Torus Ring을 제안한다. Torus Ring은 계층 링과 완전히 동일한 복잡도를 가지면서도 지역 링간의 연결 방법만을 변경한 형태의 상호 연결 망이다. 이 연결 망은 역방향 인접 링에 대한 요청에서 흡수의 이득을 봉으로써 평균 흥 수를 감소시킨다. 또한 접근의 지역성을 고려하지 않은 균등분포의 가정 하에서도 평균 흡수의 기대 값에서 계층 링과 동일한 값을 가지며, 실제 병렬 프로그램이 수행되는 환경에서는 인접 링에 대한 통신 비율이 증가할 가능성이 크기 때문에 더 큰 흡수의 이익을 기대할 수 있다. 실험 결과 상호 연결 망의 요청과 응답의 지연 시간 단축되었으며, 이러한 응답 지연 시간의 단축이 수행 시간을 최대 7%까지 감소시키는 결과를 가져 왔다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.7
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• pp.1390-1406
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• 1994

This study deals with the DMCLP(Delay constrained Minimum Cost Loop Problem)-one of problems arising in the design of local access computer networks. The problem consists of finding a set of rings to satisfy the traffic requirements of end user terminals. In the problem, the objective is to minimize the total link cost. This paper presents heuristic algorithm which consists of two phases for this problem, under the constraints that the number of nodes served by a single ring is limited and network mean delay is dropped within the desired time. The algorithm is derived using the clusters obtained by the existing MCLP(Minimum Cost Loop Problem) algorithm and a trade-off criterion explained in the paper. Actually, simulation results in that the proposed algorithm in this paper produces better solution than the existing MCLP algorithm modified. In addition, the algorithm has the relatively short running time.

• The KIPS Transactions:PartC
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• v.10C no.2
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• pp.179-184
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• 2003

One of the remarkable problems in PIM-DM (Protocol Independent Multicast - Dense Mode) is the join latency time, increasing for specific periods. The reason of this problem is proved to the confusion of flooding prune message and leave prune message. We propose a new solution to this problem, reducing the average join latency by 37.4%, and prove the proposed solution by network simulation.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.9
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• pp.182-189
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• 2014

A tapped delay line time-to-digital converter (TDC) can be easily implemented using internal carry chains in a field-programmable gate array, and hence, its use is widespread. However, the tapped delay line TDC suffers from performance degradation because of differences in the delay times of dedicated carry chains. In this paper, a dual edge measurement method is proposed instead of a typical step signal to the delay cell to compensate for the performance degradation caused by wide-delay cells in carry chains. By applying a pulse of a fixed width as an input to the carry chains and using the time information between the up and down edges of the signal pulse, the timing accuracy can be increased. Two dedicated carry chain sites are required for the dual edge measurements. By adopting the proposed dual edge measurement method, the average delay widths of the two carry chains were improved by more than 35%, from 17.3 ps and 16.7 ps to 11.2 ps and 10.1 ps, respectively. In addition, the maximum delay times were improved from 41.4 ps and 42.1 ps to 20.1 ps and 20.8 ps, respectively.

• Journal of the Korean Society of Radiology
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• v.15 no.2
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• pp.93-100
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• 2021

The purpose of this study is to find out the factors that affect the patient's exposure dose during the abdominal CT scan using the bolus tracking technique, and reducing the radiation exposure to the patient during the abdominal CT scan using the bolus tracking technique by adjusting the delay time according to the corresponding factor. The experiment was divided into two parts, and the first experiment was conducted with 300 patients There were 188 males and 112 females, and their average age was 58±12.18(19~85). In the second experiment, 150 subjects (100 males and 50 females) who were undergoing their follow-up examination among the first experiment subjects, and the difference in dose before and after was compared by applying the delay time according to the influencing factor. As a result of the first experiment, there was a relationship between the arrival time of the contrast media and the heart rate, and it was found that the arrival time decreased as the heart rate increased for both men and women. As a result of the second experiment, the average dose of CTDIvol and DLP before/after applying the delay time according to the heart rate decreased 4.98 mGy and 5.33 mGy·cm in the male group, and 3.54 mGy and 3.88 mGy·cm in the female group. By applying proper delay time according to the patient's heart rate during abdominal CT scan with the bolus tracking technique, the radiation exposure dose of the patient can be reduced.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.1
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• pp.1-8
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• 1999

In order to provide appropriate Quality of Service(QoS) guarantee to each traffic flow in intergrated service networks, an efficient traffic scheduling algorithm as well as resource reservation must be adopted in host and transit routers. In this paper, a new efficient fair queueing algorithm which adopts a linearly increasing virtual time is presented. The proposed algorithm is fair and the maximum and mean delay guaranteed of each flow are less than those of the SCFQ(self clocked fair queueing) algorithm which is one of the most promising traffic scheduling algorithm, while providing low implementation complexity as the SCFQ scheme. And, it has the better isolation provided than SCFQ, which means that each flow is much less influenced by the violating traffic flows provided its allocated bandwidth gurantee. The fairness of the proposed algorithm is proved and simulation results of maximum and mean delay presented.

• Communications for Statistical Applications and Methods
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• v.5 no.2
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• pp.383-389
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• 1998

시스템에 대한 예방 관리 모형을 고려한다. 시스템이 고장을 일으키면 즉시 최소 수리가 이루어지고 임의로 방문하는 전문 관리인에 의해 시스템을 점검했을 때 연속하는 고장의 수가 적정 개수이상이거나 또는 시스템의 총 작동 시간이 적정 시간이상이면 시스템을 동일한 것으로 교체한다고 한다. 적절한 비용을 부과한 다음 시스템의 단위 시간당 평균 비용을 계산하고 그 비용을 최소화하는 최적의 점검 속도를 찾는다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3A
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• pp.267-277
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• 2011

Like other wireless network protocols, IEEE 802.15.4 adopts CA (Collision Avoidance)algorithm to avoid the early collision of a new packet by randomizing its first transmission time rather than its immediate delivery. The traditional CA scheme of IEEE 802.15.4, however, selects the random access time from the predetermined range without considering the degree of current congestion. It probably causes either a long delay to settle in the suitable range for the current network load or frequent clashes especially during the long lasting heavy traffic period. This paper proposes an ACA(Adaptive Collision Avoidance) algorithm adapting the initial backoff range to the undergoing collision variations. It also introduces a mathematical model to predict the performance of ACA algorithm added to IEEE 802.15.4. With only small deviations from corresponding simulations, our analytical model shows that ACA technique can improve the throughput of IEEE 802.15.4 by up-to 41% maximally in addition to shortening the packet delays.

• The KIPS Transactions:PartA
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• v.16A no.5
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• pp.347-356
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• 2009

Precise branch prediction is a critical factor in the IPC Improvement of modern microprocessor architectures. In addition to the branch prediction accuracy, branch prediction delay have a profound impact on overall system performance as well. However, it tends to be overlooked when the architects design the branch predictor. To tolerate branch prediction delay, this paper proposes Early Start Prediction (ESP) technique. The proposed solution dynamically identifies the start instruction of basic block, called as Basic Block Start Address (BB_SA), and the solution uses BB_SA when predicting the branch direction, instead of branch instruction address itself. The performance of the proposed scheme can be further improved by combining short interval hiding technique between BB_SA and branch instruction. The simulation result shows that the proposed solution hides prediction latency, with providing same level of prediction accuracy compared to the conventional predictors. Furthermore, the combination with short interval hiding technique provides a substantial IPC improvement of up to 10.1%, and the IPC is actually same with ideal branch predictor, regardless of branch predictor configurations, such as clock frequency, delay model, and PHT size.