• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2004.09a
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• pp.211-219
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• 2004

A new alloy definition will be presented concerning increasing demands for the board level reliability of miniaturized interconnections. The damage mechanism for LFBGA components on different board finishes is not quite understood. Further demands from mobile phones are the drop test, characterizing interface performance of different package constructions in relation to decreased pad constructions and therefore interfaces. The paper discusses the characterization of interfaces based on SnPb, SnPbXYZ, SnAgCu and SnAgCuInNd ball materials and SnAgCuInNd as solder paste, the stability after accelerated tests and the description of modified interfaces stric시y related to the assembly conditions, dissolution behavior of finishes on board side and the influence of intermetallic formation. The type of intermetallic as well as the quantity of intermetallics are observed, primaliry the hardness, E modules describing the ability of strain/stress compensation. First results of board level reliability are presented after TCT-40/+150. Improvement steps from the ball formulation will be discussed in conjunction to the implementation of lead free materials. In order to optimize ball materials for area array devices accelareted aging conditions like TCTs were used to analyze the board level reliability of different ball materials for BGA, LFBGA, CSP, Flip Chip. The paper outlines lead-free ball analysis in comparison to conventional solder balls for BGA and chip size packages. The important points of interest are the description of processability related to existing ball attach procedures, requirements of interconnection properties and the knowledge gained the board level reliability. Both are the primary acceptance criteria for implementation. Knowledge about melting characteristic, surface tension depend on temperature and organic vehicles, wetting behavior, electrical conductivity, thermal conductivity, specific heat, mechanical strength, creep and relaxation properties, interactions to preferred finishes (minor impurities), intermetallic growth, content of IMC, brittleness depend on solved elements/IMC, fatigue resistance, damage mechanism, affinity against oxygen, reduction potential, decontamination efforts, endo-/exothermic reactions, diffusion properties related to finishes or bare materials, isothermal fatigue, thermo-cyclic fatigue, corrosion properties, lifetime prediction based on board level results, compatibility with rework/repair solders, rework temperatures of modified solders (Impurities, change in the melting point or range), compatibility to components and laminates.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.5
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• pp.414-420
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• 2010

This paper presents a validation of the accuracy of a reduced order model(ROM) and the efficiency of the design optimization using a Proper Orthogonal Decomposition(POD) to transonic wing/fuselage system. Three dimensional Euler equations are solved to extrude snapshot data of the full order aerodynamic analysis, and then a set of POD basis vectors reproducing the behavior of flow around the wing/fuselage system is calculated from these snapshots. In this study, reduced order model constructed through this procedure is applied to several validation cases, and then it is confirmed that the ROM has the capability of the prediction of flow field in the space of interest. Additionally, after the design optimization of the wing/fuselage system with the ROM is performed, results of the ROM are compared with results of the design optimization using response surface model(RSM). From these, it can be confirmed that the design optimization with the ROM is more efficient than RSM.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.821-831
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• 2019

The 9.12 earthquake (2016.9.12., M_L=5.8) and Pohang (2017.11.15., M_L=5.4) caused social and economic damage, resulting in a greater public interest in earthquakes than in the past. In the U.S., Japan and Chile, which have high frequency of earthquakes, infrastructure facilities are already managed based on probabilistic seismic hazard analysis (PSHA) and ground motion prediction equation (GMPE) to prepare for and respond to seismic disasters. In South Korea, the aforementioned PSHA and GMPE models have been developed independently through individual researchers. However, the limited disclosure of basic data, calculation methods, and final results created during the model development poses a problem of deploying new data without updating the earthquake that occurs every year. Therefore, this paper describes how to create flatfile, which is the basic data of GMPE, and how to process for seismic waves, and how to create intensity measures.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.5
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• pp.2655-2660
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• 2016

Background: Prostate cancer is the second most common male cancer and remains a leading cause of cancer death worldwide. Heterogeneity regarding recurrence, tumor progression and therapeutic response reflects the inadequacy of traditional prognostic factors and underlies interest in new genetic and molecular markers. In this work, we studied the prognostic value of the expression of 9 proteins, Ki-67, p53, Bcl-2, PSA, HER2, E-cadherin, $p21^{WAF1/Cip1}$, $p27^{Kip1}$ and $p16^{ink4a}$ in prostate cancer. Materials and Methods: We conducted a retrospective study of 50 prostate cancers diagnosed in Pathology Department of Farhet Hached Hospital, Sousse, Tunisia, during a period of 12 months. Clinico-pathological data and survival were investigated. Protein expression was analyzed by immunohistochemistry on archived material. Results: Expression or over-expression of Ki-67, p53, Bcl-2, PSA, HER2, E-Cadherin, $p21^{WAF1/Cip1}$, $p27^{Kip1}$ and $p16^{ink4a}$ was observed in 68%, 24%, 32%, 78%, 12%, 90%, 20%, 44% and 56% of cases, respectively. Overall five-year survival was 68%. A statistically significant correlation was observed between death occurrence and advanced age (p=0.018), degree of tumor differentiation (p=0.0001), perineural invasion (p=0.016) and metastasis occurrence (p=0.05). Death occurrence was significantly correlated with the expression of p53 (p=0.007), Bcl-2 (p=0.02), Ki-67 (p=0.05) and $p27^{Kip1}$ (p=0.04). Conclusions: The p53, Bcl-2, Ki-67 and $p27^{Kip1}$ proteins may be useful additional prognostic markers for prostate cancer. The use of these proteins in clinical practice can improve prognosis prediction, disease screening and treatment response of prostatic cancer.

• Journal of KIISE
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• v.43 no.12
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• pp.1396-1403
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• 2016

In streaming data analysis where underlying data distribution may be changed or the concept of interest can drift with the progress of time, the ability to adapt to concept drift can be very powerful especially in the process of incremental learning. In this paper, we develop a general framework for an adaptive incremental classifier on data stream with concept drift. A distribution, representing the performance pattern of a classifier, is constructed by utilizing the distance between the confidence score of a classifier and a class indicator vector. A hypothesis test is then performed for concept drift detection. Based on the estimated p-value, the weight of outdated data is set automatically in updating the classifier. We apply our proposed method for two types of linear discriminant classifiers. The experimental results on streaming data with concept drift demonstrate that the proposed adaptive incremental learning method improves the prediction accuracy of an incremental classifier highly.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.1
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• pp.93-99
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• 2005

Up to date, the life extension of industrial plant structures has been strongly required in the field of iron-manufacturing company, atomic or power generation company and so on. Fault monitoring, maintenance of aging structural components, safety assessment and residual life prediction may be recognized as typical and/or practical methods in terms of life extension methods. Based on the construction of damage scenario, precise analysis method and development of the risk or reliability assessment, a number of studies have been carried out in this viewpoint. In conjunction with the finite element analysis technique, a practical procedure for the safety assessment of iron-manufacturing plant structures was developed in this paper with a particular interest in furnace. By virtue of the detailed finite element analyses for blust furnace under an operational condition, the validity of the proposed procedure for safety assessment was presented.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1082-1082
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• 2001

Extrusion is one of the most important processes in polymer industry. The characterization of the polymer melt during processing will improve this process noticeably, One possibility of characterizing the actual processed polymer melt is the inline near infrared (NIR) spectroscopy, With this method several polymer properties can be observed during processing, e.g. composition, moisture ormechanical properties of the melt. For this purpose probes for transmission and reflection measurements have been developed, withstanding the high temperatures and pressures appearing during extrusion process (tested up to 300$^{\circ}C$ and 10 ㎫). For the transmission system an optical bypass was developed to eliminate disturbing spectral influences and hence increase the long term stability, which is the prerequisite for an industrial application. Measurements in transmission and reflection produced comparable results (or blending processes, where the prediction error was less than 1%. An optimum RMSEP of only 0.24% was found for preprocessed polymer blends measured in transmission on a laboratory extruder. A transflection measurement allowed for the first time the recording of relevant NIR-spectra in the screw area of an extruder. The application to a (PE+PP) blending process delivered promising results. This new measurement mode allows the observation of the ongoing processes within the screw area, which is of maximum Interest for reactive extrusion processes. Due to economic reasons the calibration transfer between different extrusion systems is also of high importance. Investigations on simulated and real-world spectra showed that a calibration transfer is possible. A new method alternatively to the well-known direct standardization procedures was developed, which is based on an automatic data pretreatment. This procedure delivers comparable results for the calibration transfer. Overall this paper presents concepts, components and algorithms for the inline near infrared (NIR) spectroscopy for polymer extrusion, which allows the use of it in a real industrial extrusion process.

• The Korean Journal of Applied Statistics
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• v.23 no.6
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• pp.1169-1178
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• 2010

This article consider a performance model selection based on AIC under unbalanced deign in linear mixed effect models. Vaida and Balanchard (2005) proposed conditional AIC for model selection in linear mixed effect models when the prediction of random effects is of primary interest. Theoretical properties of cAIC and related criteria have been investigated by Liang et al. (2008) and Greven and Kneib (2010). However, all of the simulation studies were performed under a balanced design. Even though functional form of AIC remain same even under the unbalanced deign, it is worthwhile to investigate performance of AIC based model selection criteria under the unbalanced design. The simulation study in this article shows how unbalancedness affects model selection in linear mixed effect models.

• The Korean Journal of Applied Statistics
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• v.15 no.2
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• pp.395-403
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• 2002

In the third phase of the response surface methods, the first-order model is assumed and the curvature of the response surface is checked with a fractional factorial design augmented by centre runs. We further assume that a true model is a quadratic polynomial. To choose an optimal design, Box and Draper(1959) suggested the use of an average mean squared error (AMSE), an average of MSE of y(x) over the region of interest R. The AMSE can be partitioned into the average prediction variance (APV) and average squared bias (ASB). Since AMSE is a function of design moments, region moments and a standardized vector of parameters, it is not possible to select the design that minimizes AMSE. As a practical alternative, Box and Draper(1959) proposed minimum bias design which minimize ASB and showed that factorial design points are shrunk toward the origin for a minimum bias design. In this paper we propose a robust AMSE design which maximizes the minimum efficiency of the design with respect to a standardized vector of parameters.

• Journal of the Korean Society of Earth Science Education
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• v.7 no.3
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• pp.293-302
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• 2014

The purpose of this study is to investigate the effects of research project program of science process skills and science-related attitudes for high school students. This study were accompanied by 72 junior students of G High School who were reorganized as students whose research subject was closely related to chemistry. These students went through 28 periods of 14 sessions of research project program, were tested before and after the study on their science process skills and science-related attitudes. A simple questionnaire afterwards to get their thoughts on this program, was surveyed. The results are as follows. First, the research project program was effective in the science process skills (p<0.01). There was a statistically meaningful difference in the subcategory of deduction, setting up hypotheses, finding variables, building experiments, graphing and interpreting data. Although there was an increase in the average scores of prediction, operant definition, and generalization factors, it was not statistically meaningful (p>0.05). Second, the research project program showed an increase in the post-test of the science-related attitudes but was not statistically meaningful (p>0.05). In terms of subcategoty, the social importance of science, criterion of scientists, application of scientific attitude, and enjoyment of science classes were statistically meaningful (p<0.05). Third, according to the survey of research project program, there was an increase in creating a research problem and solving it by oneself as well as in participating with other teammates to solve a problem. But the most difficult thing was when the experiment failed during the research was processing. The curiosity and interest, towards objects around all lives and science classes after the program done, were increased.