• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.3
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• pp.474-477
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• 2003

In this paper, we have designed the p-type SiGe MOSFET and analyzed the electrical characteristics over the temperature range or 300K and 77K. When the gate voltage is biased to -1.5V, the threshold voltage values are -0.97V and -1.15V at room temperature and 77K, respectively. We know that the operating characteristics of SiGe MOSFET is superior to the basic Si MOSFET which the threshold voltage is -1.36V.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.08a
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• pp.146-154
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• 2004

Evaluating the risk of collision quantitatively plays a key role in developing the expert system of navigation and collision avoidance. This study suggested and developed a new approach to the evaluation by using the sech function as an alternative to the existing methods of appraising the collision risk. This study also investigated and built up theoretically how to determine the gradient coefficients in this approach and suggested the appropriate values as much as applicable. Finally this study analyzed thoroughly how to determine the threshold function of avoiding time and developed the appropriate equation.

• Journal of Communications and Networks
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• v.16 no.3
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• pp.293-300
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• 2014

As energy harvesting communication systems emerge, there is a need for transmission schemes that dynamically adapt to the energy harvesting process. In this paper, after exhibiting a finite-horizon online throughput-maximizing scheduling problem formulation and the structure of its optimal solution within a dynamic programming formulation, a low complexity online scheduling policy is proposed. The policy exploits the existence of thresholds for choosing rate and power levels as a function of stored energy, harvest state and time until the end of the horizon. The policy, which is based on computing an expected threshold, performs close to optimal on a wide range of example energy harvest patterns. Moreover, it achieves higher throughput values for a given delay, than throughput-optimal online policies developed based on infinite-horizon formulations in recent literature. The solution is extended to include ergodic time-varying (fading) channels, and a corresponding low complexity policy is proposed and evaluated for this case as well.

• Journal of the Korean Data and Information Science Society
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• v.8 no.1
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• pp.85-89
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• 1997

In this paper, we consider a random replacement model with minimal repair, which is a generalization of the random replacement model introduced Lee and Lee(1994). It is assumed that a system is minimally repaired when it fails and replaced only when the accumulated operating time of the system exceeds a threshold time by a supervisor who arrives at the system for inspection according to Poisson process. Assigning the corresponding cost to the system, we obtain the expected long-run average cost per unit time and find the optimum values of the threshold time and the supervisor's inspection rate which minimize the average cost.

• JSTS:Journal of Semiconductor Technology and Science
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• v.2 no.3
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• pp.170-172
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• 2002

The epilayer of vertically stacked, self-assembled InAs Quantum Dots (QDs)was grown by MBE with solid sources in non-cracking K-cells, and the sample was fabricated to a FET structure using a conventional technology. The device characteristic and performance were studied. At 77K and room temperature, the threshold voltage shift values are 0.75V and 0.35 V, which are caused by the trapping and detrapping of electrons in the quantum dots. Discharging and charging curves form the part of a hysteresis loop to exhibit memory function. The electrical injection of confined electrons in QDs products the threshold voltage shift and memory function with the persistent electron trapping, which shows the potential use for a room temperature application.

• Transactions of the Korean Society of Mechanical Engineers
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• v.8 no.2
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• pp.141-144
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• 1984

The fatigue limits of crack initiation and propagation on the edge elliptical notched semi-infinite plate under completely reversed fatigue stress are determined theoretically. Assuming that the crack initiation and propagation occur when stress intensity factors of notched plate reach the critical values obtained from critical micro-crack length under plain fatigue limit loading and the threshold stress intensity factory, respectively, the fatigue limits of crack initiation and propagation are obtained. The induced theoretical fatigue limit of crack initiation is expressed in terms of plain fatigue limit, critical micro-crack length and notch shape. The one of crack propagation is in terms of threshold stress intensity factor, plain fatigue limit and notch shape. These theoretical results are showed to be in good agreement of Frost's experimental data.

• International Journal of CAD/CAM
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• v.6 no.1
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• pp.81-87
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• 2006

This paper describes a method for extracting surfaces from multi-material CT (Computed Tomography) data. Most contouring methods such as Marching Cubes algorithm assume that CT data are composed of only two materials. Some extended methods such as [3, 6] can extract surfaces from the multi-material (non-manifold) implicit representation. However, these methods are not directly applicable to CT data that are composed of three or more materials. There are two major problems that arise from fundamentals of CT. The first problem is that we have to use n(n-1)/2 threshold values for CT data contains n materials and select appropriately one threshold value for each boundary area. The second is that we cannot reconstruct only from CT data in which area three or more materials are adjacent each other. In this paper, we propose a method to solve the problems by using image analysis and demonstrate the effectiveness of the method with application examples construct polygon models from CT data of machine parts.

• Transactions on Electrical and Electronic Materials
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• v.18 no.5
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• pp.250-252
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• 2017

High-performance full swing logic inverters were fabricated using amorphous 1 wt% Si doped indium-zinc-oxide (a-SIZO) thin films with different channel layer thicknesses. In the inverter configuration, the threshold voltage was adjusted by varying the thickness of the channel layer. The depletion mode (D-mode) device used a TFT with a channel layer thickness of 60 nm as it exhibited the most negative threshold voltage (-1.67 V). Inverters using enhancement mode (E-mode) devices were fabricated using TFTs with channel layer thicknesses of 20 or 40 nm with excellent subthreshold slope (S.S). Both the inverters exhibited high voltage gain values of 30.74 and 28.56, respectively at $V_{DD}=15V$. It was confirmed that the voltage gain can be improved by increasing the S.S value.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.773-776
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• 2003

In this paper, we have designed the p-type SiGe MOSFET and analyzed the electrical characteristics. When the gate voltage is biased to -1.5V, the threshold voltage values are -0.97V and -1.15V at room temperature and 77K, respectively. We know that the operating characteristics of SiGe MOSFET is superior to the basic Si MOSFET which the threshold voltage is -1.36V.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.1
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• pp.186-194
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• 1997

The objective of this study is to develope knock control algorithms which can increase engine power without causing frequent knock occurrence. A four cylinder spark-ignition engine is used for the experiments to develop knock control algorithms which use block vibration signals. Knock occurrence is detected accurately by using knock threshold values which consider the difference of transmission path of each cylinder. Spark timing is controlled both simultaneously and individually. With the simultaneous control, torque gain is achieved by retarding the spark timing on knock occurrence in propotion to the knock intensity. The individual knock control algorithm results in higher torque gain than the simultaneous knock control algorithm. The knock occurrence frequency of the individual knock control algorithm is about twice the value of the simultaneous knock control algorithm results. Both control algorithms give similar torque gain of about 3% when they are optimized.