• Wind and Structures
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• 제36권2호
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• pp.91-103
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• 2023

Tuned liquid dampers (TLDs) are increasingly being used as efficient dynamic vibration absorbers to mitigate wind-induced vibration in super high-rise buildings. However, the damping characteristics of screens and the control effectiveness of actual structures must be investigated to improve the reliability of TLDs in engineering applications. In this study, a numerical TLD model is developed using computational fluid dynamics (CFD) and a simulation method for achieving the coupled vibration of the structure and TLD is proposed. The numerical results are verified using shaking table tests, and the effects of the solidity ratio and screen position on the TLD damping ratios are investigated. The TLD control effectiveness is obtained by simulating the wind-induced vibration response of a full-scale structure-TLD system to determine the optimal screen solidity ratio. The effects of the structural frequency, damping ratio, and wind load amplitude on the TLD performance are further analyzed. The TLD damping ratio increases nonlinearly with the solidity ratio, and it increases with the screens towards the tank center and then decreases slightly owing to the hydrodynamic interaction between screens. Full-scale coupled simulations demonstrated that the optimal TLD control effectiveness was achieved when the solidity ratio was 0.46. In addition, structural frequency shifts can significantly weaken the TLD performance. The control effectiveness decreases with an increase in the structural damping ratio, and is insensitive to the wind load amplitude within a certain range, implying that the TLD has a stable damping performance over a range of wind speed variations.

• 한국안전학회지
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• 제38권2호
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• pp.52-59
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• 2023

Due to the routine nature of social distancing in accordance with the COVID-19 pandemic, the logistics industry is under rapid development, given that offline demand is focused on online platforms. The number of warehouse workplaces and workers are steadily increasing per annum, and the industrial accident rate of transportation, warehouse, and telecommunication industries to which warehouse employees belong is higher than the total industrial accident rate in Korea. In previous studies, warehouse workers reported exposure to health hazards such as musculoskeletal disorders due to the handling of heavy objects and improper working postures. Accordingly, in this study, a survey was conducted to investigate symptoms of musculoskeletal disorders with focus on parcel delivery workers nationwide. The questionnaire included a musculoskeletal disorder symptom survey table to identify information such as worker occupational history, work type, and signs or symptoms of musculoskeletal disorders. Survey response data from 453 people were obtained to determine the influence of delivery business characteristics on occupational musculoskeletal disorders, and the influencing factors were analyzed. Based on the results, in the analysis of pain with respect to body part, the duration, degree, and frequency of pain were highest in the leg part, and as a result, the average value for the leg part exhibited a significant difference from those of other body parts. In addition, 52.32% of workers exhibited symptoms of musculoskeletal disorders, and a high number of patients with musculoskeletal disorders was observed in the work group with less than three years of service and with ages ranging from 30-39. The results of this study can serve as basic data for the derivation of a management plan that meets the characteristics of musculoskeletal disorders that impact logistics workers overburdened with work due to the rapid increase in parcel delivery volume in accordance with an increase in online consumption.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 춘계학술대회
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• pp.115-117
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• 2022

화이트박스 암호 기법은 암호 키 정보를 소프트웨어 기반 암호화 알고리즘에 섞어 암호 키의 노출을 막는 방식이다. 화이트박스 암호 기법은 허가되지 않은 역공학 분석으로 메모리에 접근하여 기밀 데이터와 키를 유추하기 어렵게 만들어서 종래의 하드웨어 기반의 보안 암호화 기법을 대체하는 기술로 주목받고 있다. 하지만, 암복호화 과정에서 연산 결과와 암호 키를 숨기기 위해 크기가 큰 룩업테이블을 사용하기 때문에 암복호 속도가 느리고, 메모리 사이즈가 커지는 문제가 발생한다. 특히 최근 저가, 저전력, 경량의 사물인터넷 제품들은 제한된 메모리 공간과 배터리 용량 때문에 화이트박스 암호을 적용하기 어렵다. 또한, 실시간 서비스를 지원해야 하는 네트워크 환경에서는 화이트박스 암호의 암복호화 속도로 인해 응답 지연 시간이 증가하여 통신 효율이 열화된다. 따라서 본 논문에서는 S.Chow가 제안한 AES 기반 화이트박스(WBC-AES)를 사용하여 속도와 메모리 요구조건을 만족할 수 있는지 실험 결과를 토대로 분석한다.

• 한국동물학회지
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• 제12권4호
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• pp.109-113
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• 1969

Podisus maculiventris 幼蟲의 各齡期別 및 成蟲의 雌雄別 捕食量을 調査하기 爲하여 幼蟲의 2, 3, 4, 5齡 및 成蟲의 雌雄別로 1區를 3組씩으로 하여 各區 및 各組에 幼蟲의 境遇는 5, 10, 20mg 그리고 成蟲의 境遇는 20, 40, 50mg 되는 미국흰불나방 幼蟲을 供給하여 P. maculiventris의 捕食量을 調査하였으며 Holling 의 "disc" equation에 依하여 計算된 豫想捕食量을 求하여 觀察捕食量과 豫想捕食量과의 相關關係를 調査하였다. 1. 幼蟲의 境遇는 5, 10, 20mg 의 diet level에 따라 2齡때는 11.23, 18.4, 20.7mg, 3齡때는 12.3, 12.37, 28.3mg, 4齡때는 18.17, 40.3, 42.7mg 그리고 5齡때는 51.7, 92.7, 130.2mg의 捕食量을 보여 주었다. 2. 成蟲의 境遇는 20, 40, 50mg의 diet level에 따라 雄性은 528, 740.3, 545.1mg, 雌性은 516.5, 627.5, 603.3mg의 捕食量을 보여주었다. 3. 幼蟲 및 雌雄成蟲에 觀察捕食量과 豫想捕食量과의 사이에는 相互 比例關係가 있었다.

• 농촌계획
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• 제20권4호
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• pp.253-262
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• 2014

This, an association research for design-improvement and model-development of exhibition shops at rural tourism communities, is to secure objective data by analyzing customers' awareness-tendency of and demand for agricultural-specialty exhibition shops. Survey-questions for finding out consumers' awareness-tendency and demand were determined through brainstorming of a professional council, 30 rural communities of which visit-rate by consumers is considerably high were selected for the recruit of 200 consumers. For investigation and analysis, survey and in-depth interview were carried out at the scene with the application of frequency analysis and summarization of their opinions, which revealed that they have a strong will to visit the rural tourism communities for the purchase of agricultural specialties along with the experience of learning-program and on-the-scene direct dealing and that their viewpoint on the direct dealing at the scene was very positive. Also it was confirmed hat their satisfaction with the purchase of agricultural specialties by on-the-scene direct dealing, their pleasure at the purchase, their satisfaction with services and their intention for re-purchase of them were very high while their satisfaction with the exhibition shops was very low. With on-the-scene survey, the consumers' opinions could be listened to in depth. Almost all of them said their satisfaction with the trip to those rural tourism communities was considerably high since they could go to those communities themselves to relieve the stress from their modern life, to experience healing and to see the goods on the scene. Their satisfaction also was attributed to the fact that they have enough trust in purchase along with feeling the warm-heartedness of rural residents. As to their awareness of exhibition shops, they showed a positive response to the on-the-scene direct dealing at rural communities while they, thinking that the space in those exhibition shops was not sufficiently wide, demanded for more systematic counters in more accessible and affordable exhibition shops so that they might be more satisfied with the exhibition shops. Their demand for the necessity of exhibition shops selling agricultural specialties was found to be over 80%, which indicates that the necessity is very high. As to the suitability of function, they have the opinion that the business at those shops had better be focused on sales since they have the understanding of information when they take a trip to the rural communities, while there was another opinion: since agricultural products are seasonal items they should be exhibited and sold at the same time. More than 90% of the respondents had a positive viewpoint on direct dealing of agricultural specialties on the scene, which showed that their response to it was very high. They preferred the permanent shops equipped with roll-around table-booths. In addition, it was revealed that they want systematic exhibition shops in rural communities because they frequent those communities for on-the-scene direct purchase. The preferred type and opinion resulting from estimation of consumers' demands have been reflected for development of practical designs. The structure of variable principles has been designed so that the types of display-case and table-booth might be created. The result of this study is a positive data as a design model which can be utilized at rural communities and will be commercialized for the verification of its validity.

• 한국지반공학회논문집
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• 제28권1호
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• pp.67-77
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• 2012

본 연구에서는 조밀한 건조 사질토 지반에서 단말뚝 및 $3{\times}3$ 군말뚝에 대해 정현파를 이용하여 동적 원심모형실험을 수행하였으며, 군말뚝의 경우 말뚝 중심간격을 지름의 3배, 5배, 7배로 변화시켜 실험을 실시하였다. 실험 결과로 얻은 단말뚝과 군말뚝의 동적 p-y 곡선들을 비교하여, 말뚝 중심 간격 및 군말뚝 말뚝 위치에 따른 말뚝의 동적 군말뚝 효과를 분석하였다. 분석 결과, 첫 번째 열과 세 번째 열의 말뚝인 측면 말뚝에서 유사한 동적 p-y 거동이 나타났으며, 두 번째 열 말뚝들은 측면 말뚝들에 비해 지반반력 감소 효과가 작게 나타났다. 또한, 두 번째 열 내에서 말뚝 위치에 따른 동적 p-y 거동을 비교한 결과, 두 번째 열의 바깥 말뚝에서 중앙 말뚝보다 지반반력 감소 효과가 크게 나타났다. 실험 결과를 바탕으로 제안된 말뚝 중심 간격에 따른 p-승수 값은 측면 말뚝에서 0.28 ~ 0.77, 중앙 말뚝에서 0.55 ~ 1.0, 바깥 말뚝에서 0.39 ~ 0.87로 나타났다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권15호
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• pp.6267-6272
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• 2015

Background: Extra nodal lymphoma (ENL) constitutes about 33 % of all non-Hodgkin's lymphoma. 18-28% develops in the head and neck region. A multimodality treatment with multi-agent chemotherapy (CT) and radiotherapy (RT) is considered optimum. Materials and Methods: We retrieved the treatment charts of patients of HNENL treated in our institute from 2001-2012. The charts were reviewed and the demographic, treatment details and outcome of HNENL patients were retrieved using predesigned pro-forma. Results: We retrieved data of 75consecutive patients HNENL. Median age was 47years (Range: 8-76 years). Of the 75 patients 51 were male and 24 were female. 55patients were evaluable. The patient and tumor characteristics are summarized in Table 1. All patients were staged comprehensively with contrast enhanced computed tomography of head, neck, thorax, abdomen, pelvis and bone marrow aspiration and biopsy 66 patients received a combination multi-agent CT with CHOP being the commonest regimen. 42 patients received 4 or lesser number of cycles of chemotherapy whereas 24received more than 4 cycles chemotherapy. Post radiotherapy, 41 out of 42 patients had a complete response at 3 months. Only 21patients had a complete response after chemotherapy. All patients received radiation (mostly involved field radiation) as a part of the treatment. The median radiation dose was 45 Gray (Range: 36 Gray-50 Gray). The radiation was planned by 2D fluoro simulation based technique in 37cases and by 3 Dimensional conformal radiation therapy (3DCRT) in 36 cases. Two patients were planned by the intensity modulated radiation therapy (IMRT) technique. IMRT was planned for one thyroid and one nasal cavity primary. 5 patients experienced relapse after a median follow up of 19 months. The median survival was not reached. The estimated two and three year survival were 92.9% (95%CI- 68.6- 95.35) and 88% (95%CI- 60.82 - 92.66) respectively. Univariate analysis revealed higher stage and poorer baseline performance status to be significantly associated with worse progression free survival. 5 patients progressed (relapse or primary disease progression) after treatment. Of the 5 patients, two patients were primary orbital NHL, two patients had NHL nasal cavity and one was NHL thyroid. Conclusions: Combined modality treatment in HNENL confers excellent disease control with acceptable side effects.

• 한국식품영양학회지
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• 제26권2호
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• pp.226-233
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• 2013

비파엽을 첨가한 쌀음료의 개발에 있어서 과당, 크림, 그리고 비파엽 물 추출물의 농도는 최종 관능적인 맛과 기호도 모두에 유의적인 효과를 주고 있었으며, 비파엽 물 추출물 자체의 쓴맛과 이미를 감소시키는 주요한 첨가물은 과당이라고 결론지을 수 있었다. 그러나 비파엽을 첨가한 쌀음료는 대조구로 사용된 상용 쌀음료를 5점으로 하였을 때 반응 표면 분석의 결과로 예측된 최고 점수가 5점이 약간 못 미치는 수준인 것을 보인다. 통계적 분석 방법의 결과인 Table 2의 전체 기호도 5의 수준에 도달하기 위한 비파엽 추출물의 첨가량에 대한 과당의 첨가량의 상관 관계를 유의성이 떨어지는 항목을 배제하여 회귀식을 단순화하여 과당과 비파엽 추출물만의 식으로 나타내고, 이를 근거로 하여 과당과 비파엽이 기준시료 총 기호도의 5점에 해당하는 수준을 도달하기 위한 상호간의 관계식을 구하였다. 그 결과 과당 첨가량 = 0.618 ${\times}$(비파엽 추출물 Brix 18 고형분량)$^2$ + 0.406 ${\times}$ (비파엽 추출물 Brix 18 고형분량)으로 계산되었다. 결론적으로 비파엽 추출물의 쓴맛을 감소하는 효과는 크림이 있으나 선호도는 과당의 첨가량이 비파엽 추출물을 포함하는 쌀음료의 기호도에 더 큰 효과가 있음을 알 수 있었다.

• 대한전자공학회논문지SP
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• 제42권5호
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• pp.85-94
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• 2005

디지털 입력값과 이에 대응되는 CIEXYZ 삼 자극치 값에 대한 관계를 도출하는 기법인 디스플레이 특성화는 칼라 운영 시스템에서 정확한 색을 재현하는데 중요하다. 9개 채널 제조 응답 곡선으로부터 추정된 디스플레이 장치의 특성화는 기존 3개 채널의 계조 응답 곡선을 사용한 것 보다 성능이 향상된다. 하지만 9개 채널의 계조 응답 곡선을 사용한 디스플레이 장치의 특성화는 각각의 RGB값에 대응되는 CIEXYZ값이 분리되지 않기 때문에, 역 특성화 과정이 직접적으로 적용되지 않는다. 따라서 일반적인 경우 역 특성화 과정은 3차원 참조표를 사용하여 구현된다. 3차원 참조표를 역 특성화 과정에 적용할 경우, 결과의 정확도는 향상 되지만 많은 양의 메모리 공간과 다수의 측정 데이터가 필요한 단점이 있다. 그러므로 본 논문에서는 채널 의존적인 값의 모델링과 GOG(gain, offset gamma) 모델에 기반한 9개 채널의 역 변환 과정을 적용한 역 특성화 기법을 제안한다. 제안한 방법은 디스플레이 특성화의 정확도를 향상할 뿐 아니라 3차원 참조표 방법을 사용할 경우 요구되는 복잡도와 다수의 측정 데이터도 감소할 수 있다.

• 한국식생활문화학회지
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• 제37권1호
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• pp.1-12
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• 2022

This qualitative study analyzed various environmental factors and difficulties faced by school foodservices during the COVID-19 pandemic. Focus group interviews were conducted by enrolling 12 nutrition teachers and nutritionists. Data collected were subsequently analyzed for changes implemented during the pandemic, in hygiene management, diet management, and distribution management of the school meal. The content and method of delivery of information related to diet guidance and school foodservice by related organizations were also examined. Results of the survey show that personal hygiene (such as maintaining student-to-student distance, checking students for a fever, and hand disinfection) was duly applied, installation of table coverings and distancing between school cafeteria seats were conducted, and mandatory mask-wearing to prevent droplet transmission was enforced. Depending on the COVID-19 situation, the number of students having school meals was limited per grade, and time-spaced meals were provided. To prevent infection, menus that required frequent hand contact were excluded from the meal plan. Overall, it was difficult to manage the meal plan due to frequent changes in tasks, such as the number of orders and meal expenses. These changes were communicated by nutrition teachers and nutritionists wherein the numbers of school meals were adjusted, depending on situations arising from each COVID-19 crisis stage. Furthermore, in some schools, either face-to-face nutrition counseling was stopped entirely, or nutrition education was conducted online. Parent participation was disallowed in the monitoring of school meals, and the prohibition on conversations inside the school cafeteria resulted in the absence of communication among students, nutrition teachers, and nutritionists. Additionally, confusion in meal management was caused by frequent changes in the school meal management guidelines provided by the Office of Education and the School Health Promotion Center in response to COVID-19. In anticipation of the emergence of a new virus or infectious diseases caused by mutations in the years to come, it is suggested that a holistic, well-thought-out response manual for safe meal operation needs to be established, in close collaboration with schools and school foodservice-related institutions.