• Transactions of the Korean Society of Automotive Engineers
• /
• v.19 no.6
• /
• pp.90-96
• /
• 2011

In this study, the characteristic of fractured portion and shape on solder joints were investigated according to the thermal shock test for Automotive Application Component using Sn-3.0Ag-0.5Cu solder, which has a outstanding property as Lead-free solder. The value of pull and shear strength was decreased in principle after 432 cycles thermal shock test. In addition, fracture mode was verified by using EDS and SEM to observe fractured shape on the solder joints before and after thermal shock. In before thermal shock test, the fracture mode revealed typically solder layer's fracture mode. In after thermal shock test, we identified multiple fracture mode of the ductile and brittle fracture. Even though same composition of solder was used to experimental for estimating. the fracture mode varied on the fracture portion's height and the directional angles of shear strength. In conclusion, we identified that mechanical strength was affected on the solder layer's fracture mode.

• 보존과학연구
• /
• s.33
• /
• pp.57-67
• /
• 2012

The Uiseong Tapriri Five-Storied stone pagoda has occurred exfoliation, granular disintegration and discoloration by physical and chemical weathering factors with the major deterioration occurring due to efflorescence by salt. According to the results of SEM-EDS and X-ray diffraction analysis, salts consists of gypsum, taranakite. Artificial salt weathering tests were carried out using the same type of rocks as those in the stone pagoda. The test results showed that efflorescence occurred on the surface of the rock, and that exfoliation and granular disintegration occurred inside the rock due to salt crystallization.

• Culinary science and hospitality research
• /
• v.23 no.7
• /
• pp.183-193
• /
• 2017

The present study was conducted at a night market in the Ulsan region, with the purpose of analyzing the impact of menu quality at night markets on customers' perceived value and revisit intention. The study surveyed 323 visitors to the night market, and analyzed the results using the SPSS 18.0 statistics program. The results were the following. Firstly, the results of the exploratory factor analysis regarding menu quality at the night market showed 5 main factors, to a statistically valid and reliable degree: hygiene, price, diversity, originality, and taste. Secondly, it was found that menu quality exerts a positive influence on perceived value, with taste having the biggest influence on hedonic value, and price having the biggest influence on utilitarian value. Thirdly, it was found that menu quality further exerts a positive impact on the revisit intention, with price having the greatest influence in this regard. Fourthly, perceived value was found to have a positive influence on the revisit intention, with utilitarian value having a greater effect than hedonic value in this regard.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.29 no.3
• /
• pp.152-158
• /
• 2016

The bonding characteristics of MLCCs (multi layer ceramic capacitor, C1608) lead-free solder (SAC305) joints were evaluated through thermal shock test ($-40^{\circ}C{\sim}125^{\circ}C$, total 1,800 cycle). After the test, IMCs( intermetallic compounds) growth and cracks were verified, also shear strengths were measured for degradation of solder joints. In addition, The thermal stress distributions at solder joints were analyzed to compare the solder joints changes before and after according to thermal shock test by FEA (finite elements analysis). We considered the effects of IMCs growth at solder joints. As results, the bonding characteristics degradation was occurred according to initial crack, crack propagations and thermal stress concentration at solder-IMCs interface, when the IMCs grown to solder inside.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2023.01a
• /
• pp.315-316
• /
• 2023

본 논문에서는 딥러닝을 활용하여 KBO (Korea Baseball Organization)의 다음 시즌 플레이오프 진출 확률을 예측하는 Deep Neural Network (DNN) 시스템을 설계하고 구현하는 방법을 제안한다. 연구 방법으로 KBO 각 시즌별 데이터를 1999년도 데이터부터 수집하여 분석한 결과, 각 시즌 데이터 중 경기당 평균 득점, 타자 OPS, 투수 WHIP 등이 시즌 결과에 유의미한 영향을 끼치는 것을 확인하였다. 모델 설계는 linear, softmax 함수를 사용하는 것보다 relu, tanh, sigmoid 함수를 사용했을 때 더 높은 정확도를 얻을 수 있었다. 실제 2022 시즌 결과를 예측한 결과 88%의 정확도를 도출했다. 폭투의 수, 피홈런 등 가중치가 높은 변수의 값이 우수할 경우 시즌 결과가 좋게 나온다는 것이 증명되었다. 본 논문에서 설계한 이 시스템은 KBO 구단만이 아닌 모든 야구단에서 선수단을 구성하는데 활용 가능하다고 사료된다.

• Journal of Korea Game Society
• /
• v.12 no.3
• /
• pp.25-36
• /
• 2012

Cross-Media Storytelling(CMS) is the new method of media representation. It picks the features and the elements in one media, and uses them in another media. 'Remediation' in digital era uses the content of old media in new form based on new technology. But 'CMS' represents the basic elements of the media experience in each unique style of media. It changes the focus from the technology to experience. So CMS is the new strategy of the media not based on the new technology. Adam PESapane's (2006) is a example for this strategy. It takes the game media as a subject matter. But it expresses the meta-representation of game experience in the "stop motion animation" Especially it emphasizes the narrative chain between the usual phenomenon and the visual imagination. And it shows the possibility of representation of new media experience in the old media genre. So it suggests the conditions of CMS.

• Journal of Conservation Science
• /
• v.32 no.3
• /
• pp.365-375
• /
• 2016

This study was interpreted the forming process of surface contaminants on ten-story stone pagoda of Wongaksa temple, Seoul. Results of research, we estimated that black contaminants were formed by graphite stuck carbon in air pollution substance after that gypsum was generated by chemical weathering on stone pagoda. White contaminants were built by recrystallization of calcite that were made by decomposition of finishing materials and structure on the stone surface. To preserve a long-term of stone pagoda in Wongaksa temple, there were required that continuous monitoring, anticorrosion treatment and contaminants cleaning of protective facilities.

• Journal of Conservation Science
• /
• v.25 no.1
• /
• pp.61-76
• /
• 2009

Gwangjueupseong (Gwangju Town Wall) has been found in the site of the Asian Culture Complex (former Provincial Government of Jeonnam) by archaeological field survey. The length of the remaining wall is 85.1m, and the Town Wall consists of ten kinds of rock type. The major rock types are dacite (41.1%) and andesite (35.7%). Dacite composes main rock blocks of the wall, and andesite is used to fill the cavity between main rock blocks. These rocks look very similar to basement rocks of the Mudeung Mountain on the basis of occurrence features, magnetic susceptibility, petrological, mineralogical and geochemical properties. Also, quarrying traces were found on the southwestern slope of the mountain along the Jeungsimsa Temple valley. Thus, it is probable that the rock materials of the Gwangju Town Wall were supplied from the Mudeung Mountain and that they were transported along the Gwangju river.

• Journal of Conservation Science
• /
• v.33 no.1
• /
• pp.25-33
• /
• 2017

The stone lantern of the four guardian kings in the Beopjusa temple at Boeun was mainly made of biotite granodiorite consisting of porphyritic-textured potassium feldspar and included in ilmenite series. A base stone made of alkali granite was buried, after founded its place during an earlier restoration process. Cracking and break out are noticeable on this object. In addition, discoloration, salt crusting, and epiphytes were observed. The lantern was vulnerable in terms of physical and structural stability caused by cracking in the front and back of the light chamber and in the non-horizontal direction. According to the conservational condition of the stone lantern, structural reinforcement was carried out based on calculations, including those on the position, size, and anchor length of the titanium stiffener. Chemical and biological pollutants were washed off without damage to the surface of the stone material. Oxygenated iron pieces were replaced with titanium. Ethyl silicate was applied to the surface of the lantern for consolidation and smooth drainage.

• Korean Journal of Heritage: History & Science
• /
• v.56 no.4
• /
• pp.160-189
• /
• 2023

The Cheonjeon-ri petroglyph is inscribed with shale formation belonging to the Daegu Formation of the Gyeongsang Supergroup in the Cretaceous of the Mesozoic Era. This rock undergoes thermal alteration to become hornfels, and has a high hardness and dense texture. Rock-forming minerals have almost the same composition as quartz, alkali felspar, plagioclase, calcite, mica, chlorite and opaque minerals, but calcite is rarely detected in the weathered zone. The petroglyph forms a weathered zone with a certain depth, and there is a difference in mineral and chemical composition between weathered and unweathered zones, respectively. The CaO contents of the weathered zone were reduced by more than 90% compared to that of the unweathered zone, because calcite reacted with water and dissolved. As a result of calculating the surface weathering depth for the petroglyph with the transmission characteristics of X-rays, depth of the parts in falling off and exfoliation showed a depth of about 0.5 to 1 mm, but the weathering depth in most areas was calculated to be about 3 to 4 mm. This can be proved by the contents and changes of Ca and Sr. The surface discolorations of the petroglyph are distributed with different color density, and the yellowish brown discoloration is alternated with a thin biofilm layer, showing a coverage of 79.6%. Therefore, periodic preservation managements and preventive conservation monitoring that can effectively control the physicochemical and biological damages of the Cheonjeonri petroglyph will be necessary.