• 신재생에너지
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• 제4권3호
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• pp.5-14
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• 2008

The target for the reduction of $CO_2$ emissions, as specified in the Kyoto Protocol, can only be achieved by an extended use of renewable fuels and the increasing of the energy efficiency. The energy generation from waste gases with a reasonable content of methane like biogas can significantly contribute to reach this target. A further reduction of greenhouse gas emissions is possible by increasing the electrical efficiency using progressive technologies. Fuel cells can be highly energy conversion devices. Utilizing biogas as the fuel for fuel cell systems offers an option that is technically feasible, potentially economically attractive and greenhouse gas neutral. High temperature fuel cells that are able to operate with carbon monoxide in the feed are well suited to these applications. Furthermore, because they do not require noble metal catalysts, the cost of high-temperature fuel cells has the greatest potential to become competitive in the near future compared to other types of fuel cells.

• 소성∙가공
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• 제24권3호
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• pp.181-186
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• 2015

Many in the industrial world that consume high amounts of energy are trying to reduce energy when manufacturing their products. Energy saving during manufacturing is a cost reduction. Reduced cost is necessary for profit improvement. The Piston Under Drive Brake used in the current study is an automotive transmission part. The original machining after hot forging was changed to machining after cold forging of a plate in order to save energy and cost. Two extrusion shapes along the outer diameter caused decreased tool life because of the interrupted cut during turning. Therefore, a thickness reduction of two extrusion areas in the outer diameter was needed. The current study suggests an effective way to reduce the thickness of interrupted cut by using progressive blanking.

• International Journal of Aeronautical and Space Sciences
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• 제17권3호
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• pp.332-340
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• 2016

A design optimization is performed for the double-bolted joint in cylindrical composite structures by using a simplified analytical method. This method uses failure criteria for the major failure modes of the bolted composite joint. For the double-bolted joint with a zigzag arrangement, it is necessary to consider an interaction effect between the bolt arrays. This paper proposes another failure mode which is determined by angle and distance between two bolts in different arrays and define a failure criterion for the failure mode. The optimal design for the double-bolted joint is carried out by considering the interactive net-tension failure mode. The genetic algorithm (GA) is adopted to determine the optimized parameters; bolt spacing, edge distance, and stacking sequence of the composite laminate. A purpose of the design optimization is to maximize the burst pressure of the cylindrical structures by ensuring structural integrity. Also, a progressive failure analysis (PFA) is performed to verify the results of the optimal design for the double-bolted joint. In PFA, Hashin 3D failure criterion is used to determine the ply that would fail. A stiffness reduction model is then used to reduce the stiffness of the failed ply for the corresponding failure mode.

• 대한토목학회논문집
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• 제36권4호
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• pp.715-722
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• 2016

국내 대부분의 노선은 자갈도상궤도로 이루어져 있어, 지속적인 유지보수가 요구되고 있다. 따라서, 보다 효과적인 요지보수를 통해 비용 절감을 위해서는 예방보수를 통한 유지보수의 최적화가 필요하다. 여기에는 도상자갈층의 침하 진전모델의 확보가 필수적이다. 그러나, 자갈도상재료는 입자가 큰 조립재료로써 일반 지반재료와는 다른 거동을 보인다. 따라서, 본 연구에서는 자갈재료의 거동에 대한 이해와 침하진전모델의 합리적인 개발을 위해 개별요소해석을 수행하였으며, 입자 형상, 공극률, 하중조합 및 빈도에 따른 침하거동을 비교 분석하였다.

• ETRI Journal
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• 제33권2호
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• pp.155-162
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• 2011

The scalable extension of the H.264/AVC video coding standard (SVC) demonstrates superb adaptability in video communications. Joint source and channel coding (JSCC) has been shown to be very effective for such scalable video consisting of parts of different significance. In this paper, a new JSCC scheme for SVC transmission over packet loss channels is proposed which performs two-dimensional optimization on the quality layers of each frame in a rate-distortion (R-D) sense as well as on the temporal hierarchical structure of frames under dependency constraints. To compute the end-to-end R-D points of a frame, a novel reduced trellis algorithm is developed with a significant reduction of complexity from the existing Viterbi-based algorithm. The R-D points of frames are sorted under the hierarchical dependency constraints and optimal JSCC solution is obtained in terms of the best R-D performance. Experimental results show that our scheme outperforms the existing scheme of [13] with average quality gains of 0.26 dB and 0.22 dB for progressive and non-progressive modes respectively.

• 대한통합의학회지
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• 제9권1호
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• pp.151-161
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• 2021

Purpose : This study was to investigate the effectiveness of ESWT and plantar fascia-specific stretching exercise vs ESWT and high-load strengthening exercise in patients with chronic plantar fasciitis. Methods : The subjects were randomized to extracorporeal shock wave therapy ( ESWT, for 3 weeks) and daily plantar-specific stretching (Group I: Stretch group) or ESWT and high-load progressive strength (Group II: Strength group) performed every second day. The main outcome measures were ultrasound, visual analogue scale (VAS), and Korean Foot Function Index (KFFI). The ultrasound (plantar fascia thickness), pain intensity I, II (the most painful of the day?, the pain when you first step in the morning?) and KFFI (functional performance) were compared between the groups. Results : No significant difference was observed between the groups in the plantar fascia thickness but pain intensity I, II was significantly lower in Group 2 than in Group 1 at only 12weeks and functional performance was also significantly increased in Group 2 compared to Group 1 at only 12 weeks. Conclusion : The high-load strengthening exercise consisting of the progressive exercise protocol, resulted in superior after 12 weeks compared with plantar-specific stretching. High-load strength exercise may aid in a quicker reduction in pain and improvements in functional performance.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제24권1호
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• pp.75-80
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• 2021

Purpose: Appendicitis is the most frequent urgency in pediatric age; the aim of this study was to investigate the association of quarantine for severe acute respiratory syndrome coronavirus 2 pandemic and the incidence of pediatric appendicitis in a specific macro area. Methods: We retrospectively analyzed the medical records of consecutive patients who underwent surgical exploration for acute appendicitis in the period March-April since 2014. This specific quarantine period was divided into two phases as indicated by National government. Patient data, demographics, characteristics and outcomes were studied and evaluated comparing patients treated during quarantine especially phase 1 vs. phase 2 (March-April 2020). Results: After reviewing medical charts following the inclusion and exclusion criteria, 155 patients were studied; focusing on the final outcome, it is possible to show a decreased amount of appendicitis during phase 1 and a progressive increase during phase 2; respect to previous years, there was a statistical increase in severity of appendicitis during quarantine (gangrenous vs. phlegmonous appendicitis). Conclusion: During this specific quarantine there was a reduction in appendicitis and a progressive increase during phase 2. These results offer new perspective among disease incidences during lockdown.

• Physical Therapy Rehabilitation Science
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• 제12권3호
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• pp.310-319
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• 2023

Objective: The purpose of this study was to investigate the effects of a combination of progressive scapular stabilization exercises, neck and thoracic spine mobilization, and thermoelectric physical therapy on pain, range of motion, muscle strength, and function in patients with acute whiplash injury. Design: A randomized controlled trial design. Methods: A total of 24 subjects were included in this study. They were randomly assigned to an experimental group (n=12) that performed scapular stabilization exercises, neck and thoracic spine mobilization, and physiotherapy, and a control group (n=12) that only performed neck and thoracic spine mobilization and physiotherapy. The pre-test was conducted before the intervention and consisted of a total of 12 treatment sessions of 60 minutes each, three times a week. A posttest was conducted 4 weeks later. Pain, range of motion, muscle strength, and function were assessed before and after intervention. Results: The results of the study showed that there was a significant difference in pain reduction and range of motion and muscle strength improvement in the experimental group, and a significant difference was also found between the experimental group and the control group in terms of functional evaluation. Conclusions: The combination of exercise therapy and joint mobilization technique and physical therapy resulted in greater improvements in pain, range of motion, strength, and function assessment, contributing to improved overall function.

• 한국항만학회지
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• 제7권2호
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• pp.19-36
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• 1993

In this study for relieving traffic congestion on the main arterial in Pusan using TSM Techniques, the travel system, roadway system and signal system analyses were dine. Through these above analyses, it was shown that the peak-time periods on the main arterial were shaped between 10 : 00 and 11 : 00 in the morning and between 15 : 00 and 16 : 00 in the afternoon for the business and shopping trips. Especially, there appeared to be about 23% reduction in the average delay when roadway system management including left-turn links increased were done, about 29% reduction in the average delay when signal system management including the signal phases and timings readjusted were conducted, and about 48% reduction in average delay when roadway system and signal system management were taken into consideration simultaneously. Based upon these results, it was concluded that there might be considerably better results in the average delay if the progressive signal system analyses on the arterial were applied with the land and road widths balanced, the difference on the turning vehicles and mid-block volumes readjusted, and roadside parking traffic prohibited.

• Journal of Oral Medicine and Pain
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• 제38권1호
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• pp.29-34
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• 2013

Introduction: 모든 정복성 관절원판변위가 비정복성 관절원판변위로 진행되는 것은 아니지만 심각한 포착이나 걸림을 동반하는 정복성 관절원판변위는 비정복성 관절원판변위로 진행하게 된다. 이번 연구에서는 Locking-free Appliance(LA)를 이용한 개구운동치료의 효과를 살펴보고자 한다. Patients and Method: 후향적으로, 2010년 1월부터 2011년 12월까지 전북대학교병원 치과진료처 구강내과에서 LA를 이용한 개구운동치료를 받은 37명의 환자를 대상으로 분석을 시행하였다. 환자는 LA를 착용한 상태에서 하루 30번의 개구운동을 할 것을 교육받았다. Results: 치료를 받은 환자들 중 비정복성 관절원판변위로 악화된 환자는 없었다. 37명 중 16명의 환자들은 과두걸림 없이 개구가 가능해졌다. Mann-whitney test와 fisher's test, Chi-square test를 이용하여 분석 시, 과두걸림이 해소된 환자와 그렇지 않은 환자간의 나이, 성별, 통증유무, 과두걸림 호소 기간, 통증의 정도(VAS score)에는 통계학적으로 유의한 차이가 없었다. Conclusion: 이번 연구에서, LA를 이용한 개구운동치료 후 일부 환자는 과두걸림 없이 개구가 가능해졌고, 일부 환자는 과두걸림이 해소되지 않았으나, 비정복성 관절원판변위로 악화된 경우는 없었다. 이 치료는 기존의 전통적인 치료방법에 비해 환자의 교합장치 착용 시간이 짧고, 비용이 저렴하며, 환자의 불편함을 최소화 할 수 있다는 장점이 있다. 따라서, LA를 이용한 개구운동치료는 과두걸림을 해소하거나, 비정복성 관절원판변위로의 악화를 예방하는데 새로운 치료방법이 될 것으로 기대된다.