• 대한전자공학회논문지
• /
• 제25권7호
• /
• pp.780-790
• /
• 1988

We have studied the hot-carrier-induced degradation caused by the high channel electric field due to the decrease of the gate length of MOSFET used in VLSI. Under DC stress, the condition in which maximum substrate current occures gave the worst degradation. Under AC dynamic stress, other conditions, the pulse shape and the falling rate, gave enormous effects on the degradation phenomena, especially at 77K. Threshold voltage, transconductance, channel conductance and gate current were measured and compared under various stress conditions. The threshold voltage was almost completely recovered by hot-injection stress as a reverse-stress. But, the transconductance was rapidly degraded under hot-hole injection and recovered by sequential hot-electron stress. The Si-SiO2 interface state density was analyzed by a charge pumping technique and the charge pumping current showed the same trend as the threshold voltage shift in degradation process.

• 전자공학회논문지A
• /
• 제31A권2호
• /
• pp.9-17
• /
• 1994

This paper proposes Double queue threshold QLT(Queue Length Threshold) algorithm and Hysteresis effect QLT algorithm. as being DPS(Dynamic Priority Scheduling) techniques. in order to advance the processing of multiple class traffics. Also, the performance of the proposed algorithms is analyzed through computer simulations,and the priority scheduling is analyzed using a retrial queue with two types of calls. Our simulation results show that the performance of the proposed Double queue length threshold QLT algorithm is superior to that of the conventinal QLT algorithm for 2 or more classes delay sensitive traffics. Also we find that Hysteresis effecT QLT algorithm is better mechanism than that of the existing QLT for real time and non-real time traffics.

• International Journal of Automotive Technology
• /
• 제8권1호
• /
• pp.33-38
• /
• 2007

Since it is difficult to analytically express the Melnikov function when a dynamic system possesses multiple saddle fixed points with homoclinic and/or heteroclinic orbits, this paper investigates a vehicle model with nonlinear suspension spring and hysteretic damping element, which exhibits multiple heteroclinic orbits in the unperturbed system. First, an algorithm for Melnikov integrals is developed based on the Melnikov method. And then the amplitude threshold of road excitation at the onset of chaos is determined. By numerical simulation, the existence of chaos in the present system is verified via time history curves, phase portrait plots and $Poincar{\acute{e}}$ maps. Finally, in order to further identify the chaotic motion of the nonlinear system, the maximal Lyapunov exponent is also adopted. The results indicate that the numerical method of estimating chaotic threshold is an effective one to complicated vehicle systems.

• International Journal of Control, Automation, and Systems
• /
• 제6권2호
• /
• pp.214-222
• /
• 2008

Bode principle is applied to carry out traffic control for rate based ATM network, which guarantees the higher buffer utilization, buffer overflow-free, and well utilization of bandwidth. The principle confirms the relationship between the threshold of buffer queue and the network bandwidth, as well as the relationship between the threshold of buffer and source input rate. Theoretic warrant of the buffer threshold is proposed. The reference range of source input rate is provided in theory, which makes the source end respond to the change of network state rapidly and dynamically, and then the effect of time delay to the traffic control is avoided. Simulation results show that the better steady and dynamic performances of networks are obtained by Bode principle.

• 한국시뮬레이션학회논문지
• /
• 제14권1호
• /
• pp.33-42
• /
• 2005

Service Level Agreement (SLA) is a service providing scheme by a service class agreement between a user and a service provider SLA allows that a user can select an expected service class in various service classes provided from a service provider. Recently, SLA management is adapted to support the end-to-end Qos for service users in Beyond 3 Generation (B3G) networks. In B3G networks, SLA provides multiple service classes on access networks so that service classes should be managed to assure the service satisfaction for users. In this paper, we propose a dynamic Qos management scheme by IP traffic class controlling based on SLA in B3G networks. Also, to manage dynamic traffic service, we consider Differentiated services (Diffserv) mechanism for the resource management by SLA. An If service traffic class on SLA can be dynamically changed by Diffserv traffic management to support dynamic end-to-end Qos. Hence, in this paper, we consider the buffer threshold scheme for controlling traffic loads and the traffic level control scheme for implementing the dynamic traffic management by the SLA.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제6권9호
• /
• pp.2086-2097
• /
• 2012

A terminal-based dynamic clustering algorithm is proposed in a multi-cell scenario, where the user could select the cooperative BSs from the predetermined static base stations (BSs) set based on dynamic channel condition. First, the user transmission rate is derived based on linear precoding and per-cell feedback scheme. Then, the dynamic clustering algorithm can be implemented based on two criteria: (a) the transmission rate should meet the user requirement for quality of service (QoS); (b) the rate increment exceeds the predetermined constant threshold. By adopting random vector quantization (RVQ), the optimized number of cooperative BSs and the corresponding channel conditions are presented respectively. Numerical results are given and show that the performance of the proposed method can improve the system resources utilization effectively.

• 한국지반공학회지:지반
• /
• 제7권2호
• /
• pp.41-50
• /
• 1991

본 연구에서 공진주 실험을 수행하여 흙의 한계변형률과 간극수압의 변화를 고찰하였다. 그 결과 흙의 한계 전단 변형률은 약한 점토질 흙의 경우 1$\times$10-2%부근, 깨끗한 석영질 모래의 경우 (ASTM C-109 Ottawa Snad) 1$\times$10-3% 부근, 단단한 차산 퇴적물(Pozzolana)의 경우 1$\times$10-4% 부근임을 보여주었다. 또 깨끗한 석영질 모래의 경우구속 압력의 변화에 따라 한계변형률이 변화되는 현상을 보여주었다. 간극 수압의 경우 전단 변형률 3~4$\times$10-3% 부근에서부터 미세한 변화를 보이다가 전단변형률 1$\times$10-2%부근에서부터 현격한 증가를 보여 주었다.

• 한국지능시스템학회논문지
• /
• 제13권1호
• /
• pp.57-62
• /
• 2003

자동화 지문인식을 위한 과정에서 지문영상의 정보를 보존하면서 최적의 세선화와 특이점추출을 위한 중요한 부분은 이진화 과정이다. 이진화 과정은 그레이-스케일 레벨의 영상을 0과 255값으로 바꾸는 과정이다. 이 과정에서 적절한 기준레벨값(Threshold Value)을 설정해 주지 않으면 지문영상의 정보가 손실된다. 본 논문에서는 이진화 과정 부분에 인공지능 기법을 적용하여 입력되는 지문영상에서 실시간으로 기준레벨(Threshold)을 추출하는 방법을 제안한다. 실험결과 기존의 방법과 비교하여 좋은 성능을 보여주고 있음을 나타낸다

• 산경연구논집
• /
• 제4권2호
• /
• pp.13-19
• /
• 2013

Purpose - The paper tested the relationship between the stock markets of the Middle East and the USA with the oil price and US dollar index as threshold variables. Research design, data, and methodology - The stock price indices of the USA, the Middle East (Abu Dhabi, Jordan), WTI spot crude oil price, and US dollar index were daily returns in the research period from May 21, 2001 to August 9, 2012. Following Hansen (1999), the panel threshold regression model was used. Results - With the US dollar index as the threshold variable, a negative relationship existed between the stock price indices of Jordan and the USA but no significant result was found between the stock price indices of Abu Dhabi and the USA. Conclusions - The USA is an economic power today:even if it has a closer relationship with the US stock market, the dynamic US economy can learn about subsequent developments and plan in advance. Conversely, if it has an estranged relationship with the US stock market, thinking in a different direction and different investment strategies will achieve good results.

• 방송공학회논문지
• /
• 제22권4호
• /
• pp.496-508
• /
• 2017

본 논문은 전역적 대비를 보존하는 동시에 경계 정보를 정확히 보존할 수 있는 혼합 톤 매핑 기법 (Tone Mapping Operator: TMO)을 제안한다. 우선, 넓은 동적 영역 (High Dynamic Rangae: HDR) 영상을 낮은 동적 영역 (Low Dynamic Range: LDR) 디스플레이에 적합하게 압축하기 위해 인간의 시각 시스템 (Human Visual System: HVS)에 기반한 임계 값 대 밝기 값 (Threshold vs. Intensity: TVI) 함수와 영상의 대비를 사용하였으며 이에 따라 영상의 전역적인 대비를 보존할 수 있었다. 또한, 가이디드 영상 필터링 (Guided Image Filtering: GIF)을 이용하여 검출된 경계 정보와 변화감지역 (Just Noticeable Difference: JND) 모델의 공간적 마스킹을 이용하여 검출된 경계 정보를 결합함으로써 영상의 경계를 보존하고 출력 영상의 인지적 화질을 향상시켰다. 기존에 TMO들은 크게 전역적 톤 매핑 (Global Tone Mapping: GTM)과 지역적 톤 매핑 (Local Tone Mapping: LTM)으로 분류되었다. GTM은 전역적인 대비를 보존하며 구현이 단순해 실행시간이 빠르다는 장점이 있지만 영상의 경계 정보가 손실되며 지역적 대비를 보존하지 못하는 단점이 있었다. 반면 LTM은 영상의 지역적 대비와 경계 정보를 잘 보존하였지만 경계 영역에서의 헤일로 열화 현상의 발생과 같이 일부 영역이 부자연스럽게 표현되는 경우가 발생하였으며 GTM과 비교하여 높은 계산 복잡도를 가졌다. 따라서 본 논문에서는 GTM과 LTM의 장점을 결합하여 전역적인 대비를 보존하는 동시에 영상의 경계 정보를 보존하는 TMO를 제안하였으며 실험결과를 통해 제안하는 톤 매핑 기법이 인지적 화질 측면에서 성능이 우수한 것으로 확인되었다.