• Proceedings of the KSR Conference
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• 2007.05a
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• pp.786-791
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• 2007

Korean high speed train(HSR-350x) has adopted a combined electrical and mechanical(friction) braking system. Brake blending control unit(BBCU) controls each brake system to fulfill the required brake performances such as braking distance, deceleration and jerk. Also the braking system should be designed considering the economical management, such as effective use of generated braking energy and the minimum wear of friction materials(a pad and a brake shoe). In this paper, we establish the disc braking force pattern that reduces the wear of pad in the disc braking system by minimizing the variance of the instantaneous disk baking energy during braking time, and compare the wear mass of pad between the conventional disc braking force pattern and the established results.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.377-383
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• 2022

In today's modern society, along with the 4th industrial revolution, digitalization is rapidly progressing from everyday life to the entire industry. In the field of education, support is being provided at the government level, such as the dissemination of digital devices to create a digital educational environment, and the use of digital devices is remarkably increasing at the level of individual students as well. In the fashion design education field of universities, the number of students using tablet PCs and applications such as iPads is increasing and the scope of its application is expanding, from design concept setting and idea generation to design sketches in the early fashion design process, as well as diagramming and portfolio work. For fashion design sketching, it was found that students mainly use Procreate or Clip Studio applications with iPad. Therefore, by identifying the differentiated functions and characteristics of Procreate and Clip Studio, and examining design sketch examples using them, the possibility of effective use of iPad applications was presented and problems were also examined. Through this study, it is intended to provide basic data for fashion design education that can increase students' interest and achievement by using the iPad application.

• Journal of the Korea Convergence Society
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• v.12 no.5
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• pp.93-99
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• 2021

Recently, the miniaturization and digitalization for the inspection devices of point-of-care testing (POCT) are rapidly evolving. In the urine test, a lot of researches on index paper technology are being conducted because people can be self-diagnosed through visual color comparison using a urine test paper, Dipsick. The purpose of this study is to analyze the RGB values from the color changes on Dipstick Pad, which isused for urine test, using a smartphone camera. To this end, the primary, analytes in urine wasdiabetes-related parameters such as glucose, ketone body and pH, which is the most frequently tested elements, and we pursuited to quantify the changes in dipstick color caused from artificial urine containing different ranges of sugar, ketone body, and pH. In this experiment, changes in RGB values under bright and dark illuminances were compared, and changes in RGB value were monitored as a function of concentration of analytes under the ambient illumination of laboratory. As a result, color separation at the bright luminance region was good, but it did not appearat the low luminance region, and the changed profiles in RGB value under different illuminances was suggested to correct the problem of the color separation algorithm.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.515-524
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• 2022

The turnout system of the sleeper floating tracks (STEDEF) on urban transit is a Anti-vibration track composed of a wooden sleeper embedded in a concrete bed and a sleeper resilience pad under the sleeper. Therefore, deterioration and changes in spring stiffness of the sleeper resilience pad could be cause changes in sleeper support conditions. The damage amount of manganese crossings that occurred during the current service period of about 21 years was investigated to be about 17% of the total amount of crossings, and it was analyzed that the damage amount increased after 15 years of use (accumulated passing tonnage of about 550 million tons). In this study, parameter analysis (wheel position, sleeper support condition, and dynamic wheel load) was performed using a three-dimensional numerical model that simulated real manganese crossing and wheel profile, to analyze the damage type and cause of manganese crossing that occurred in the actual field. As a result of this study, when the voided sleeper occurred in the sleeper around the nose, the stress generated in the crossing nose exceeded the yield strength according to the dynamic wheel load considering the design track impact factor. In addition, the analysis results were evaluated to be in good agreement with the location of damage that occurred in the actual field. Therefore, in order to minimize the damage of the manganese crossing, it is necessary to keep the sleeper support condition around the nose part constant. In addition, by considering the uniformity of the boundary conditions under the sleepers, it was analyzed that it would be advantageous to to replace the sleeper resilience pad together when replacing the damaged manganese crossing.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.361-361
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• 2013

비냉각 적외선 검출소자는 빛이 전혀 없는 환경에서도 사물을 감지하는 열상장비의 핵심소자이다. 마이크로볼로미터 적외선 검출기는 상온에서 동작하며, 온도안정화를 위해 TEC를 장착하여 진공패키지로 조립된다. 패키지는 진공을 유지할 수 있도록 일반적으로 메탈로 제작되며, 단가 감소 및 생산성 증대를 위해 wafer level packaging 방법을 이용한다. 마이크로볼로미터의 특성은 패키지의 진공 변화에 매우 민감하다. 센서의 감도를 증가시키기 위해서는 진공환경을 유지해야 한다. 볼로미터 소자의 특성은 상압에서 열전도는 기판과 멤브레인 사이의 에어갭을 통해 열손실을 야기하므로 센서의 반응도가 현저히 줄어든다. 에어갭이 1 um 정도 되더라도 그 사이에 존재하는 열전도가 가능하므로 진공을 유지하여 열고립 상태를 증대시킬 수 있다. 이에 본 연구에서는 소자의 동작시 압력, 즉 진공도가 볼로미터 소자의 반응도 특성에 미치는 영향을 조사하였다. 마이크로볼로미터 소자는 $2{\times}8$ 어레이 형태로 제작하였으며, metal pad를 각 단위셀에 배치하였으며, 공통전극으로 한 개의 metal pad를 넣어 설계하였다. 흡수체로써 VOx를 사용하였으며, 열 고립구조를 위해 2.5 um 공명 흡수층의 floating 구조로 멤브레인을 형성하였다. 진공패키지는 메탈패키지를 제작하여 볼로미터 칩을 TEC 위에 장착하였으며, 신호의 감지를 위해 가변저항을 매칭시켰다. 반응도는 신호 대 잡음 값을 획득하여 소자에 도달하는 적외선 에너지에 대해 반응하는 값을 계산에 의해 얻어내는 것이다. 픽셀 크기는 $50{\times}50$ um이며, 패키지 조립 공정 후 온도변화에 따른 저항 측정을 통해 TCR 값을 얻었다. 이때 TCR은 약 -2.5%/K으로 나타났다. $2{\times}8$의 4개 단위소자에 대해 측정한 값은 균일하게 TCR 값이 나타났다. 광반응 특성은 볼로미터 단위소자에 대해서 먼저 고진공(5e-6 torr) 하에서 측정하였으며, 반응도는 25,000 V/W의 값을 나타내었고, 탐지도는 약 2e+8 $cmHz_{1/2}$/W로 나타났다. 패키지의 압력 조절을 위해 TMP 및 로터리 펌프를 이용하여 100 torr에서 1e-4 torr의 범위에서 압력조절 밸브를 이용하여 질소가스의 압력으로 진공도를 변화시켰다. 적외선 반응신호는 압력이 증가함에 따라 감소하였으며, 2e-1 torr의 압력에서 신호의 크기가 감소하기 시작하여 5 torr에서 반응도의 1/2 값을 나타냄을 알 수 있었다. 30 torr 이상에서는 신호가 잡음값 과거의 동일하여 신호대 잡음비가 1로 나타남을 알 수 있었다. 또한 진공도 변화에 대해, 흑체온도에 따른 반응도 및 탐지도의 특성을 조사한 결과를 발표한다. 반응도의 증가를 위해 진공도는 진공도는 1e-2 torr 이하의 압력을 유지해야 함을 본 실험을 통해 알 수 있었다.

• Journal of Music and Human Behavior
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• v.15 no.2
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• pp.69-92
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• 2018

The purpose of this study was to investigate whether a songwriting intervention would improve self-expression of adolescents with cochlear implants (CI). In this study, the songwriting intervention was designed to incorporate previous research findings on music perception of individuals with CIs and to provide musical experiences in which adolescents with CIs could be successful in using music resources for their self-expression. Accordingly, stepwise songwriting procedures were constructed and music technology (i.e., GarageBand as an iPad application) was used. Two adolescents with CIs participated in the intervention once a week for 8 weeks. Changes in level of participation in songwriting tasks, verbal expression, self-reports about the songwriting process were examined. The results demonstrated that the participants showed increased attempts to express themselves via music making. It was also shown that their negative perception of their ability to verbally express themselves decreased. They were observed as becoming more competent in creating music by deciding how various musical elements should be played and making rhythm or melodic patterns by themselves. These results indicate that the songwriting intervention can facilitate self-expression of adolescents with CIs. Further implications in terms of the psychosocial needs of individuals with CIs are presented.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.9
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• pp.1383-1389
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• 2013

This research was conducted to see the correlation between changes of ankle Joint Position Sense and Sway Area through Unstable Surface training. For the study, 48 healthy males and females were randomly divided into an unstable surface group(n=24) and a stable surface group(n=24). Then, they were asked to carry out the same exercise program three times a week for six weeks. The unstable surface group and stable surface group performed the exercise program on the balance exercise pad and on the hard ground, respectively. As a result, the unstable surface group displayed significantly reduced error of ankle joint position sense and sway area(p<.05). Moreover, a significant correlation between variances of ankle joint position sense and sway area was only found in the unstable surface group. In conclusion, this study demonstrated that there was a significant correlation between changes of ankle joint position sense and sway area through proprioceptive sense training on the unstable surface.

• Journal of Korean Orthopaedic Sports Medicine
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• v.7 no.2
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• pp.75-83
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• 2008

과사용 증후군은 정상적인 조직에 최대하 부하(submaximal stress)가 지속되어 발생하는 것이다. 이와 같은 현상은 연부조직의 접합부(junction)에서 주로 일어나며 힘의 전달이 집중되는 곳, 조직의 역학적 성질이 변화되는 곳, 그리고 성장시 빨리 변화하는 성질이 있는 곳에 주로 생긴다. 근육의 불균형이 과사용 증후군의 가장 많은 원인이다. 과거의 부상 이후 부적절한 재활치료 및 각형성 또는 회전 부정정렬(angular and rotational malalignment) 등이 과사용 증후군의 원인이 될 수 있다. 스포츠 훈련 방법의 실수로도 과사용 증후군이 생길 수 있다. 전방 슬관절 동통시 감별해야 할 질환들은 jumper's knee, 슬개건염 혹은 대퇴 사두건염, Osgood-Schlatter 병, Sinding-Larsen-Johansson 병, 슬개골 연골 연화증, 슬개골 전(prepatellar) 혹은 슬개골 하(infrapatellar) 점액낭염, Hoffa's fat pad의 염증, 그리고 특발성 전방 슬관절 동통 증후군(idiopathic anterior knee pain syndrome)등이 있다. 후방 슬관절 통증의 원인 질환으로는 만성 슬와근 염좌, 슬괵건 점액낭염, 경골 골간단의 피로 골절 등이 포함되며 외측 슬관절 통증의 원인으로는 장경대 충돌 증후군(iliotibial band friction syndrome)등이 있을 수 있다. 이외 과사용 증후군과 관련된 슬관절 통증의 원인으로 다분 슬개골(multipartite patella), 내측 경골 스트레스 증후군(medial tibial stress syndrome), 박리성 골연골염, 반월상 연골의 퇴행성 변화 등이 있을 수 있다. 과사용 증후군의 진단 및 치료의 일반적인 접근법은 다섯가지 단계의 프로그램으로 요약될 수 있다. 첫째, 원인 요소를 확인하고, 둘째, 요소를 변경시키고, 셋째, 통증을 조절하고, 넷째, 능동적 재활을 시키고, 그리고 다섯째, 유지시키는 것이다.

• Polymer(Korea)
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• v.30 no.6
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• pp.519-524
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• 2006

Poly(4-vinyl pyridine) (PVP) and its copolymers, poly(4-vinyl pvridine- co-acrylamide) and poly(4-vinyl pyridine-co-allylamine), were synthesized and evaluated for application to organic solder-ability preservatives (OSP). The copolymers were synthesized by radical polymerization of vinyl pyridine in the presence of acrylamide or allylamine as a comonomer. Various kinds of polymers with different chemical composition were synthesized by varying the feed ratio of monomers and their low $M_w$ polymers can be obtained by adding 2-mercaptoethanol as a chain transfer agent during poly-merization. All the polymers showed good adhesion properties on Cu pad when they were spin-coated. Especially, allylamine -containing copolymers showed both good adhesion and solubility properties. Also, they exhibited better thermal stability than PVP homopolymer and such thermal properties were changed depending on the chemical composition and their $M_w$, which were evidenced by the measurement of oxygen induced temperature (OIT). From the OIT measurement, poly(4-vinyl pyridine- co-allylamine) was thermally stable up to $230^{\circ}C$ for 70 min in the 100% oxygen environment. As a result, allylamine-containing copolymers can be considered as a promising OSP coating material that has excellent thermal and adhesive properties applicable to the present microelectronic package processes.

• Journal of Adhesion and Interface
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• v.3 no.2
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• pp.40-44
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• 2002

We invested effect of the keeping-time of uncured composite and thermal aging, of cured composite on adhesive strength for rubber-brass coated steel cord composite in this study. We also evaluated how the adhesive strength affects to tire endurance. Using PAD adhesion specimen, peel adhesive strength was measured. The uncured composite was kept for several days up to 35 days in factory. Cured composite was also kept for 5 and 10 days at $85^{\circ}C$ in dry oven. Peel adhesive strength was decreased with increasing keeping-time and showed lower value with increasing thermal aging time. The lower peel adhesive strength, the lower tire-endurance. This fact was caused by the humidity and thermal aging which affected in the decrease of adhesive strength of the rubber-steel cord composite and resulted in interface fracture between rubber and steel cord. This phenomenon was confirmed from SEM investigation and tire-endurance. It was just known that corrosion of steel cord's surface and aging of adhesive layer strongly affected to decrease of adhesive strength. This resulted in directly decreasing tire-endurance.