• Journal of KIISE:Computer Systems and Theory
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• v.32 no.3
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• pp.133-147
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• 2005

Various types of ray-tracing methods are used to predict the quantity measures of radiation illumination, the uniformity of illumination, radiation performance of LCD BLU(Hack-Light Unit). The uniformity of radiation illumination is one of the most important design factor of BLU and is usually controlled by the diffusive-ink pattern printed on the bottom of light-guide panel of BLU. Therefore it is desirable to produce an improved (ideally, the optimal) ink pattern to achieve the best uniformity of radiation illumination. In this paper, we applied the Welder-Mead simplex-search method among various direct search method to compute the optimal ink pattern. Direct search methods are widely used to optimize the functions which are often highly nonlinear, unpredictably discontinuous, and nondifferentiable, The ink-pattern controlling the uniformity of radiation illumination is one type of these functions. In this paper, we found that simplex search methods are well suited to computing the optimal diffusive-ink pattern. In extensive numerical testing, we have found the simplex search method to be reasonably efficient and reliable at computing the optimal diffusive-ink pattern. The result also suggests that optimization can improve the functionality of simulation tools which are used to design LCD BLU.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.10
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• pp.1203-1210
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• 2007

The multibeam surveillance radar is a state-of-art of 3D radar technology. It applies the stacked beam-on-received realized by a digital beamformer. In this paper, a method of a low target altitude extraction for multibeam surveillance radar in multipath environmental condition is proposed and investigated. The model of multipath propagation and radar generation produced from the low altitude target in multibeam surveillance radar and the nelder-mead simplex multipath reduction(NMSMR) method which enables a reliable low altitude target extraction in specular reflection situations are described. The proposed algorithm is simulated to confirm the effectiveness of proposed algorithm in accordance with a various of target altitudes and radar frequencies.

• Journal of Biomedical Engineering Research
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• v.29 no.3
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• pp.231-238
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• 2008

Nelder-Mead downhill simplex method (DSM), a kind of deterministic optimization algorithms, has been used extensively for magnetoencephalography(MEG) dipolar source localization problems because it dose not require any functional differentiation. Like many other deterministic algorithms, however, it is very sensitive to the choice of initial positions and it can be easily trapped in local optima when being applied to complex inverse problems with multiple simultaneous sources. In this paper, some modifications have been made to make up for DSM's limitations and improve the accuracy of DSM. First of all, initial point determination method for DSM using magnetic fields on the sensor surface was proposed. Secondly, Univariant-DSM combined DSM with univariant method was proposed. To verify the performance of the proposed method, it was applied to simulated MEG data and practical MEG measurements.

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.1044-1049
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• 1999

Fermentation characteristics for the production of honey wine (mead and melomel) was investigated. Among the yeast strains tested, Saccharomyces bayanus showed higher alcohol production and better fermentability than the other strains at low temperature. Optimum pH and temperature for the production of honey wine by Saccharomyces bayanus were pH 4.0 and $20^{\circ}C$, respectively, and optimum soluble solid content of diluted honey solution for the fermentation was between 24 and $27^{\circ}Brix$. Total acidity and pH of honey wine (mead) did not change considerably during the whole period of fermentation, but those of Tangerine and Japanese apricot honey wine (melomel) changed during the fermentation. As the fermentation progressed, reducing sugar decreased continuously until the late period of fermentation, while alcohol content increased continuously during the same period. After fermentation of 21 days, honey wine consisted of about $8.5{\sim}9.1^{\circ}Brix$ of soluble solid, $1.90{\sim}2.32%$ of reducing sugar with the conversion rate of $90{\sim}92%$. After 21 days of fermentation, alcohol contents of mead fermented with polyflower and acasia flower were 13.3 and 13.7%, respectively. Final alcohol content was not affected significantly by the source of honey. While pH of the osmotically extracted fruit honey juice decreased rapidly to pH $2.92{\sim}2.97$ after 13 days of fermentation, total titratable acidity of Tangerine and Japanese apricot honey wine were 0.30 and 0.53%, respectively. After 13 days of fermentation, reducing sugar of fruit honey wines were reduced to $2.03{\sim}2.87%$, alcohol content were reached up to 13.1 and 12.5% for Tangerine and Japanese apricot honey wine, respectively. Generally, honey extracted fruit juices were fermented more efficiently than diluted honey juice.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1512-1515
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• 1987

The buffer circuit having minimum delay time is designed and analyzed in this paper. Considering the parasitic components of the MOS transistor, the optimal transistor size ratio between the individual buffer stages is presented. This paper's result is better than that of the Mead and Conway's analysis [1] with respect to both delay time and total area that buffer occupies.

• 전기의세계
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• v.26 no.2
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• pp.95-98
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• 1977

Commercially available fuel oil for power plant contains relatively much sulphur, which means accordingly high content sulphur deoxide in exhaust gas. Sulphur deoxide has been identified as the worst-pollutant caused by thermal power generation. This paper primarily deals with the stack gas diffusion effects of various parameters, namely vertical stability, wind velocity, exhaust gas velocity, stack height, etc., on the ground concentration. thereof the relation between stack height and maximum plant capacity is analyzed from the standpoint of air pollution prevention. The limit capacity is calculated by means of mean concentration introducing Mead and Lowry coefficient respectively.

• The Korean Journal of Applied Statistics
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• v.9 no.1
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• pp.1-15
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• 1996

This paper discusses the effectiveness of an infection rate under a certain disease on an immunity rate by a protective inoculation. A sequence of dependense models concerning the infection rate is derived by defining conditionally nested binary random variables for the analysis of polytomous data with hierarchical response scale. Maximum likelihood estimates based on the marginal log-likelihood functin are obtained numerically in the Nelder and Mead's(1965) simplex method.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1990.10a
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• pp.101-104
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• 1990

The program which could determine cross-sectional dimensions of the box girder bridge at tile stage of preliminary design was developed using the optimal technique in this study. It could minimize the cost and time required in the design of box girder bridges and the construction with the prestressed precast segmental method. Objective cost function consisted of four independent variables such as widths and depth of the cross-section. The Nelder-Mead method was used to solve the nonconstrained nonlinear problem like this.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.6 s.52
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• pp.19-28
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• 2006

Most conventional model updating methods must use mathematical objective function with experimental modal matrices and analytical system matrices or must use information about the gradient or higher derivatives of modal properties with respect to each updating parameter. Therefore, most conventional methods are not appropriate for complex structural system such as bridge structures due to stability problem in inverse analysis with ill-conditions. Sometimes, moreover, the updated model may have no physical meaning. In this paper, a new FE model updating method based on a hybrid optimization technique using genetic algorithm (GA) and Holder-Mead simplex method (NMS) is proposed. The performance of hybrid optimization technique on the nonlinear problem is demonstrated by the Goldstein-Price function with three local minima and one global minimum. The influence of the objective function is evaluated by the case study of a simulated 10-dof spring-mass model. Through simulated case studies, finally, the objective function is proposed to update mass as well as stiffness at the same time. And so, the proposed hybrid optimization technique is proved to be an efficient method for FE model updating.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.1
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• pp.68-74
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• 1985

In this Paper, we present a non-doglegging channel routing system for If layout using standard cells. This system produces a final two-layer wiring pattern in the horizontal track between two rows, each of which is a linear placement of standard cells of identical heights, satisfying the given net list specification. The layout of CMOS cell library Including nine primitive cells used in this paper is represented in CIF (Caltech Intermediate Form) using λ(Lambda) of 2 microns in Mead-Conway layout representation scheme. The cell dimension and 1/0 characteristics such as name, position and layer type of the pins are stored in Component Library to be used in the channel routing progranl, CROUT. 4 subprogram, NET-PLOT, was used to report a schemdtic layout result, and another subprogram, NETCIF was used to with a full-fledged final layout representation in GIF, A test run for realizing a dynamicmaster-slave D flip-flop with set/reset using primitive cells was shown to take 4 CPU seconds on VAX 11/780.