• Journal of the Korean Society of Safety
• /
• v.16 no.4
• /
• pp.39-46
• /
• 2001

It is noted that KS D 3507 pipe steel has several problems when it is used as a city gas pipe at medium pressure. So new pipe steel, KS D 3631, was developed in order to be used as a pipe for medium and low pressure and now it is being substituted for D 3507. In this study, several mechanical tests, such as tensile test, microhardness test, and Charpy impact test were conducted to get material properties of D 3507 and D 3631 pipe steels. And also microstructures at the weld and heat affected zones were observed for the two materials. From the Charpy test results $K_{IC}/$ was estimated for the upper and lower shelf and the critical crack length is calculated for supposed axial semi-elliptical surface cracks. And the burst pressure is estimated as a function of wear depth for a defective D 3631 pipe by using the finite element method. The burst pressure is also calculated for pipes with an axial crack by using the published equations.

• ETRI Journal
• /
• v.35 no.1
• /
• pp.109-119
• /
• 2013

Static testing of analog-to-digital (A/D) and digital-to-analog (D/A) converters becomes more difficult when they are embedded in a system on chip. Built-in self-test (BIST) reduces the need for external support for testing. This paper proposes a new static BIST structure for testing both A/D and D/A converters. By sharing test circuitry, the proposed BIST reduces the hardware overhead. Furthermore, test time can also be reduced using the simultaneous test strategy of the proposed BIST. The proposed method can be applied in various A/D and D/A converter resolutions and analog signal swing ranges. Simulation results are presented to validate the proposed method by showing how linearity errors are detected in different situations.

• Journal of the Semiconductor & Display Technology
• /
• v.3 no.4
• /
• pp.19-27
• /
• 2004

The characteristic evaluation of A/D converter is to measure the linearity of the converter. The evaluation of the linearity is to measure the DNL, INL, gain error and offset error in the various test parameters of A/D converter. Generally, DNL and INL are to be measured by the Histogram Test Algorithm in the DSP-based ATE environment. And gain error and offset error are to be measured by the calculation equation of the measuring algorithm. It is to propose the new Concurrent Histogram Test Algorithm for the test of the housekeeping A/D converter used in the CDMA cellular phone. Using the proposed method, it is to measure the DNL, INL, gain error and offset error concurrently and to show the measured results.

• Elastomers and Composites
• /
• v.53 no.4
• /
• pp.220-225
• /
• 2018

Resilient pads play a major role in reducing the impact of loads on a rail in a rail-fastening system, which is essentially used for a concrete track. Although a compression set test is commonly used to measure the durability of a resilient pad, the static spring constant is often observed to be different from the fatigue test. In this study, a modified compression set test method was proposed to monitor the variations in the compression set and static spring constant of a resilient pad with respect to temperature and time. In addition, the life of the resilient pad was predicted by performing an acceleration test based on the Arrhenius equation.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2008.10a
• /
• pp.62-65
• /
• 2008

In this paper, we estimated the D147 mode test, which is introduced as a new emission test mode for the driving car using diesel fuel. And we compared the D147 test mode, Lug-Down3 test mode and no load acceleration test mode. And the exhaust gas concentration between the three modes was compared. The exhaust concentration at the D147 mode is lower than the exhause concentration at the Lug-Down 3 mode and higher than that at the no load acceleration test mode. Also the correlation factor was estimated between the D147 mode and Lug-Down 3 mode.

• Journal of the military operations research society of Korea
• /
• v.34 no.1
• /
• pp.79-98
• /
• 2008

The purpose of this paper is to find the desirable R&D policies in defense area by analyzing causality between GDP and R&D investments in government, private, defense sectors. We have five variables which are composed of GDP, total R&D investment, R&D investments in government, private and defense sectors to figure out the causality between R&D investment in defense sector and other components. In the course of analysis on causality, we took the unit root test of variables to prevent spurious regression. Also we need to take cointegration test about non-stationary variables before the causality test. According to these test results, we took the causality test using ECM(Error Correction Model) for the models which have cointegrating relations. And we took ordinary Granger causality test for model which doesn't have a long-run stationary relationship. As a result of the causality test, it was shown that there exists the long-nu causality to GDP and R&D investments in government and private sectors from other variables. However, there doesn't exist the causality to defense R&D investment from other variables. We found that there doesn't exist the causality between R&D investments in defense and private sectors, and that they are independent.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.1
• /
• pp.131-136
• /
• 2013

TSV based 3D ICs have been widely developed with new problems at die and IC levels. It is imperative to test at post-bond as well as pre-bond to achieve high reliability and yield. This paper introduces a new testable design technique which not only test microscopic defects at TSV input/output contact at a die but also test interconnect defects at a stacked IC. IEEE 1500 wrapper cells are augmented and through at-speed tests for pre-bond die and post-bond IC, known-good-die and defect free 3D IC can be massively manufactured+.

• Journal of Digital Convergence
• /
• v.17 no.10
• /
• pp.273-282
• /
• 2019

The purpose of study was to examine and compare the self-esteem, interpersonal relationship, happiness, and college adjustment between Type D and non-Type D personality among nursing students. Subjects included a total 181 nursing students (Type D personality: n=53, non-Type D personality: n=128). Data were collected through personal interviews using a questionnaire. The collected date were analyzed using a ${\chi}^2$-test, Fisher's exact test, and independent t-test. There were significant differences on self-esteem, interpersonal relationship, happiness, and college adjustment between Type D and non-Type D personality among nursing students. Self-esteem showed significant differences in degree of adaption, interpersonal relationship in religion, happiness in economic status, college adjustment in religion and degree of adaption (Type D personality subjects). Type D personality lowered self-esteem, interpersonal relationship, happiness, and college adjustment in nursing students. Strategies for Type D personality in nursing students are needed to increase self-esteem, interpersonal relationship, happiness, and college adjustment.

• Fashion & Textile Research Journal
• /
• v.20 no.3
• /
• pp.353-359
• /
• 2018

In this study, fused deposition modellig(FDM) 3D printing technology has been applied directly to polyester voil fabric to produce 3D printed lace/voil composite fabrics. A stereolithograpy(STL) file with a lace type 3D modelling under the various thickness were prepared and transformed into a g-code file using a g-code generator. The extrusion conditions for FDM 3D printing were controlled by 50mm/s of nozzle speed, $235^{\circ}C$ of nozzle temperature, $40^{\circ}C$ of heating bed temperature. 3D printed lace/voil composite fabriscs manufactured by 3D printing based on FDM using a thermoplactic polyurethane(TPU) filaments were obtained. To evaluate the mechanical properties and washability of the fabricated 3D printed lace/voil composite fabric, KES-FB system test, washing fastness test and dry cleaning resistance test were conducted. As 3D printing thickness increased, KOSHI, NUMERI, and FUKURAMI of 3D printed lace/voil composite fabric increased. From the results of the primary hand value test, 3D printed lace/voil composite fabrics were confirmed to be applicable to women's summer garments. As a result of the washability and dry cleaning resistance test of the 3D printed lace/voil composite fabrics, all samples were graded 4-5.

• Journal of Applied Reliability
• /
• v.9 no.3
• /
• pp.233-248
• /
• 2009

PAM(Power Amplifier Module) is the important part of a mobile phone transmitter. It amplifies the strength of signal transmitting from a mobile phone to base stations enough to resist noise or interference. In this paper reliability assessment criteria for the PAM are established in terms of quality certification test and lifetime test. The former quality certification test comprises general performance test and environmental test. Items which pass the test undergo lifetime test which guarantees the extent of mean lifetime with certain confidence.