• International Journal of Reliability and Applications
• /
• v.7 no.2
• /
• pp.187-201
• /
• 2006

In this paper, we derive recurrence relations for the single and product moments of progressively Type-II right censored order statistics from half logistic distribution. Next, we derive the maximum likelihood estimators (MLEs) of the location and scale parameters of the half logistic distribution. In addition, we use the setup proposed by Balakrishnan and Aggarwala (2000) to compute the approximate best linear unbiased estimates (ABLUEs) of the location and scale parameters. Finally, we point out a simulation study to compare between the efficiency of the techniques considered for the estimation.

• Proceedings of the IEEK Conference
• /
• 2000.07b
• /
• pp.661-664
• /
• 2000

A workflow expresses the How of persons and things related to a business. To improve efficiency of a business, it is important to grasp and evaluate the actual situation of the current business. Till now, researches on workflows have been done almost on once business and these results can not be simply applied to food business. Besides, it is also important how to evaluate a food business workflow with a specific standard. In this paper, we propose a modeling method of food business by using hierarchical Petri net. Then we propose a concept, called throughput, as a standard to evaluate the workflows. Finally we show a method how to compute throughput and meanwhile apply a Petri net tool, Design/CPN, to do simulation of computing throughput. Our simulation result shows the modeling method and computation method of throughput are reasonable and useful.

• Journal of International Society for Simulation Surgery
• /
• v.1 no.2
• /
• pp.57-61
• /
• 2014

We present a robust 3D facial reconstruction method using a single image generated by face-specific super resolution technique. Based on the several consecutive frames with low resolution, we generate a single high resolution image and a three dimensional facial model based on it. To do this, we apply PME method to compute patch similarities for SR after two-phase warping according to facial attributes. Based on the SRI, we extract facial features automatically and reconstruct 3D facial model with basis which selected adaptively according to facial statistical data less than a few seconds. Thereby, we can provide the facial image of various points of view which cannot be given by a single point of view of a camera.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.582-583
• /
• 2007

The distribution engineers experience some difficulty in getting to the voltage measuring sites because of severe traffic congestion and the long-distance feeders. Also, the 1,600,000 distribution transformers dispersed on the distribution feeder make it difficult to select the voltage measuring site properly and compute the voltage appropriateness ratio accurately. Accordingly in this paper, an on-line fuzzy operation and control strategy is designed based on the ubiquitous environments in order to improve the inefficiency of the existing off-line ULTC operation and control strategy. The simulation tool is designed in Visual C++ MFC language to show the effectiveness of the proposed strategy. And then it is proved by the simulation works.

• Proceedings of the KIEE Conference
• /
• 1994.11a
• /
• pp.252-257
• /
• 1994

A non-uniform finite-difference Thin Film Transistor Simulation Program (TFTSP) has been developed for hydrogenated amorphous silicon TFTs. TFTSP was developed to remove as many of simplifying assumptions as possible and to provide flexibility in the modeling of TFTs so that different model assumptions may be analyzed and compared. In order to insure its usefulness and versatility as an analytic and design tool it is important for the code to satisfy a number of conditions. However, at the beginning stage of the program development, this paper shows that the code can compute the static terminal characteristics of a-Si:H TFTs under a wide range of bias conditions to allow for comparison of the model with experiment. Some of those comparisons include transfer characteristics and I-V characteristics. TFTSP will be refined to conveniently model the performances of TFTs of different designs and to analyze many anomalous behaviors and factors of a-Si:H TFTs.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.1
• /
• pp.34-40
• /
• 2012

Flux linkage of phase windings or phase inductance is an important parameter in determining the behavior of a switched reluctance motor (SRM) [1-8]. Therefore, the accurate prediction of inductance at aligned and unaligned rotor positions makes a significant contribution to the design of an SRM and its analytical approach is not straightforward due to nonlinear flux distribution. Although several different approaches using a finite element analysis (FEA) or curve-fitting tool have been employed to compute phase inductance [2-5], they are not suitable for a simple design procedure because the FEA necessitates a large amount of time in both modeling and solving with complexity for every motor design, and the curve-fitting requires the data of flux linkage from either an experimental test or an FEA simulation. In this paper, phase inductance at aligned and unaligned rotor positions is estimated by means of numerical method and magnetic equivalent circuit as well, and the proposed approach is analytically verified in terms of the accuracy of estimated inductance compared to inductance computed by an FEA simulation.

• Communications for Statistical Applications and Methods
• /
• v.11 no.3
• /
• pp.643-655
• /
• 2004

L$_1$-estimator in the linear regression model is widely recognized to have superior robustness in the presence of vertical outliers. While the L$_1$-estimation procedures and algorithms have been developed quite well, less progress has been made with the hypothesis test in the multiple L$_1$-regression. This article suggests computer-intensive resampling approaches, jackknife and bootstrap methods, to estimating the variance of L$_1$-estimator and the scale parameter that are required to compute the test statistics. Monte Carlo simulation studies are performed to measure the power of tests in small samples. The simulation results indicate that bootstrap estimation method is the most powerful one when it is employed to the likelihood ratio test.

• Communications for Statistical Applications and Methods
• /
• v.17 no.3
• /
• pp.377-390
• /
• 2010

In the case of time-series analysis, it is often more convenient to rely on the frequency domain than the time domain. Spectral density is the core of the frequency-domain analysis that describes autocorrelation structures in a time-series process. Possible ways to estimate spectral density are to compute a periodogram or to average the periodogram over some frequencies with (un)equal weights. This can be an attractive tool to measure the similarity between time-series processes. We employ the metrics based on a smoothed periodogram proposed by Park and Kim (2008) for the classification of different classes of time-series processes. We consider several lag windows with unequal weights instead of a modified Daniel's window used in Park and Kim (2008). We evaluate the performance under various simulation scenarios. Simulation results reveal that the metrics used in this study split the time series into the preassigned clusters better than do the raw-periodogram based ones proposed by Caiado et al. 2006. Our metrics are applied to an economic time-series dataset.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2012.05a
• /
• pp.187-195
• /
• 2012

This paper deals with numerical computations of cryogenic flows around turbopump inducer. Firstly, we introduce numerical methods to compute compressible/incompressible cryogenic two-phase flow. As a validation problem, computation results of 2 dimensional/axi-symmetric cryogenic flow will be presented. In this process, various cavitation model will be compared. Finally, numerical simulation of 3 dimensional turbopump inducer will be presented.

• Journal of the Korea Society for Simulation
• /
• v.10 no.3
• /
• pp.71-82
• /
• 2001

Considering material handling delay which occurs between storage and processing stations, we propose an algorithm to estimate the required storage capacity, i.e., number of aisles and number of openings in vertical and horizontal directions in each aisle, of an automated storage/retrieval(AS/R) system. Due to the random nature of storage and retrieval requests, proportion of single and dual commands is not known in advance. Two design criteria, maximum permissible overflow probability and maximum allowable storage/retrieval(S/R) machine utilization, are used to compute the storage capacity. Most of studies assume that storage capacity of AS/R systems is given, although it is a very important decision variable in the design phase. Therefore, the proposed model can be effectively used in the design phase of new AS/R systems.