• Journal of Korea Multimedia Society
• /
• v.2 no.3
• /
• pp.355-365
• /
• 1999

In this paper, we present JPAS(Java Package for Array Sharing) which is a Java Package for sharing arrays of data on a cluster of workstations. It allows us to divide an array of data into several pieces, and to place each piece on a different host. JPAS uses Java RMI so that the entire array can be accessed by a location transparent interface which is similar to that of a distributed shared memory system. JPAS is portable and easy to use since it is implemented using pure Java. In order to reduce network overhead, JPAS allows programmers to use their prior knowledge of the application. Data consistency can be maintained through the value updating methods defined for all the elements of an array. We developed parallel programs which use JPAS, and tested them on a cluster of workstations. The test results show that JPAS is a parallel programming tool with reasonably good performance.

• Journal of the Microelectronics and Packaging Society
• /
• v.17 no.2
• /
• pp.21-28
• /
• 2010

Creep behaviors of the solder balls in a flip chip package assembly during thermal cycling test is investigated.. A material models used in the finite element analysis are viscoplastic model introduced by Anand and creep model called partitioned model. Experiment of two temperature cycles using moir$\acute{e}$ interferometry is conducted to verify the reliability of material models for the analysis of thermo-mechanical behavior. Bending deformations of the assemblies and average strains of the solder balls due to temperature change and dwell time are investigated. The results show that time-dependent shear strain of solder by the partitioned model is in excellent agreement with those by moir$\acute{e}$ interferometry, while there is considerable difference between results by Anand model and experiment. In this paper, the partitioned model is employed for the time-dependent creep analysis of the FC-PBGA package. It is also shown that the thermo-mechanical stress becomes relaxed by creep behavior at high temperature during temperature cycles.

• Journal of Industrial Convergence
• /
• v.17 no.4
• /
• pp.9-14
• /
• 2019

This paper presents several problems that can occur in the development of the ultra-compact LED package of less than 1.0mm and introduces the solution to them. In the existing mold structure, since the upper and lower core parts are integrated, various errors have occurred due to the roughness of EDM in the small model, which is a limiting factor in further reducing the mold size. As a countermeasure, the prefabricated model was presented in an earlier study to overcome the obstacles to the development of a ultra-compact LED package. In this paper, several problems have been found during the fabrication of prototypes as a starting work to produce the results for the presented model. The types are suggested and the solutions are discussed. And by changing the existing 2-row structure to 3-row structure in the same size lead frame, the aspect of efficient production is considered. The experimental procedure verifies the proposed solution and conducts a test to produce a prototype to confirm that a good product can be produced.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.41 no.10
• /
• pp.1005-1009
• /
• 2017

In this study, the shock resistance of a gas turbine package subjected to a shock load caused by non-contact underwater explosion was investigated using numerical analysis. To perform shock analysis, the time-history shock load was calculated according to BV-043 (German Navy Regulation). The direct transient response analysis in the time domain for the simplified Whole Engine Model (WEM) was performed using the calculated shock load. In addition, the structural integrity of a detailed model was evaluated by considering the shock load transferred to each component. As a result, it was confirmed that the safety factor was at least 1.0 as compared with the reference stress. Finally, the structural and functional integrity of the Engine Management System (EMS) of the gas turbine package was verified through an actual shock test.

• Journal of the Microelectronics and Packaging Society
• /
• v.13 no.4
• /
• pp.1-7
• /
• 2006

A major failure mode for wafer level chip size package (WLCSP) is thermo-mechanical fatigue of solder joints. The mechanical strains and stresses generated by the coefficient of thermal expansion (CTE) mismatch between the die and printed circuit board (PCB) are usually the driving force for fatigue crack initiation and propagation to failure. In a WLCSP process peripheral or central bond pads from the die are redistributed into an area away using an insulating polymer layer and a redistribution metal layer, and the insulating polymer layer affects solder joints reliability by absorption of stresses generated by CTE mismatch. In this study, several insulating polymer materials were applied to WLCSP to investigate the effect of insulating material. It was found that the effect of property of insulating material on WLCSP reliability was altered with a solder ball layout of package.

• The Bulletin of The Korean Astronomical Society
• /
• v.39 no.1
• /
• pp.54.2-54.2
• /
• 2014

IGRINS (Immersion GRating Infrared Spectrograph) is a high spectral resolution near-infrared spectrograph that has been developed in a collaboration between the Korea Astronomy & Space Science Institute and the University of Texas at Austin. By using a silicon immersion echelle grating, the size of the fore optics is reduced by a factor of three times and we can make a more compact instrument. One exposure covers the whole of the H- and K-band spectrum with R=40,000. While the operation of and data reduction for this instrument is relatively simple compared to other grating spectrographs, we still need to operate three infrared arrays, cryostat sensors, calibration lamp units, and the telescope during astronomical observations. The IGRINS Instrument Control Software consists of a Housekeeping Package (HKP), Slit Camera Package (SCP), Data Taking Package (DTP), and Quick Look Package (QLP). The SCP will do auto guiding using a center finding algorithm. The DTP will take the echellogram images of the H and K bands, and the QLP will confirm fast processing of data. We will have a commissioning observations in 2014 March. In this poster, we present the performance of the software during the test observations.

• Journal of Korean Institute of Industrial Engineers
• /
• v.12 no.2
• /
• pp.101-108
• /
• 1986

Computer programs for IBM PC/XT/AT or compatibles, are presented for running 9 nonparametric tests. They include sign test, Wilcoxon signed rank test, Mann-Whitney Wilcoxon test, Kruskal-Wallis test, Kolmogorov-Smirnov one sample and two sample tests, Kendall and Spearman rank correlation coefficient tests, and Chi square test for contingency table. Each program is written with BASIC language and is combined into a statistical package, 'NONPARA'. It is easily accessible through the menu programs. The alogorithms on which each test is based, are also explained and 3 examples are given.

• Toxicological Research
• /
• v.23 no.2
• /
• pp.173-177
• /
• 2007

The GLP contains specific language concerning characterization of the test, control and reference substances used in toxicity studies. This paper will describe and discuss what types of documents are required to support test/reference substance characterization under GLP system. The purpose of this article is to present an overview of data needed in the characterization package that will adequately define the substance. Most sponsors use a certificate of analysis (COA) to communicate the test sub-stance characterization status information to the contracting research organizations. The COA should provide the test $material^{\circ}{\phi}s$ characterization results, substance storage requirements, expiration dates, verification of the collection of the retention sample, archival location of the data to support the characterization and GLP compliance status of the characterization.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.06a
• /
• pp.315-316
• /
• 2009

본 논문에서는 1W 급 이상의 고출력 LED 용 패키지로서 세라믹 LTCC 적층 패키지의 방열 특성을 평가하고 열해석 결과와의 차이에 대해 고찰하였다. 특히, 세라믹 패키지의 방열 특성을 향상시키기 위해 Thermal Via와 Heat slug를 LED Chip 하단부에 위치시켰을 때 방열 특성을 평가하기 위해 Transient Thermal Test를 이용하여 각각의 경우에 대한 열저항을 평가하여 방열 특성의 항상 정도를 확인하였으며, 열해석 시뮬레이션을 통해 얻은 결과와 비교하였다. 평가 결과 Heat slug를 배치한 패키지가 열저항이 $8^{\circ}C/W$로서 가장 우수한 특성을 보여주었으며, 열해석 결과와의 차이에 대해서는 광출력으로 방출된 전력을 계산하여 보정함으로써 $1^{\circ}C$ 이하의 편차를 보여주는 결과를 얻을 수 있었다.

• Korean System Dynamics Review
• /
• v.15 no.4
• /
• pp.61-84
• /
• 2014

This study aims to explore the development and application of a simulated skills package designed to improve nursing students' knowledge integration and their system thinking(ST) skills about congestive heart failure(CHF) and to identify the change in students' ST levels using a ST-based learning approach. A simulated learning support package was developed by nurse educators and ST experts. The developed program was implemented with 35 third-year nursing students from S university in Seoul. The subjects improved their ST skills regarding CHF after intervention. Mean test scores for students completing the program were significantly higher than pre-intervention scores, including measures of direction of causality, polarity of causal relationship, feedback loop, polarity of feedback loop (reinforcing, balancing) and time delay (t=2.26~6.53, p=.030~p<.001). It is suggested that more educational programs be developed on various topics in order for nursing students to improve their ST skills as well as knowledge integration in clinical nursing practicum packages.