• Steel and Composite Structures
• /
• 제42권1호
• /
• pp.91-106
• /
• 2022

Concrete-filled square stainless steel tubes (CFSSST), which possess relatively large flexural stiffness, high corrosion resistance and require simple joint configurations and low maintenance cost, have a great potential in constructional applications. Despite that the use of stainless steel may result in high initial cost compared to their conventional carbon steel counterparts, the whole-life cost of CFSSST is however considered to be lower, which offers a competitive choice in engineering practice. In this paper, a comprehensive experimental and numerical program on 24 CFSSST stub column specimens, including 3 austenitic and 3 duplex stainless steel square hollow section (SHS) stub columns and 9 austenitic and 9 duplex CFSSST stub columns, has been carried out. Finite element (FE) models were developed to be used in parametric analysis to investigate the influence of the tube thickness and concrete strength on the ultimate capacities more accurately. Comparisons of the experimental and numerical results with the predictions made by design guides ACI 318, ANSI/AISC 360, Eurocode 4 and GB 50936 have been performed. It was found that these design methods generally give conservative predictions to the ultimate capacities of CFSSST stub columns. Improved calculation methods, developed based on the Continuous Strength Method, have been proposed to provide more accurate estimations of the ultimate resistances of CFSSST stub columns. The suitability of these proposals has been validated by comparison with the test results, where a good agreement between the predictions and the test results have been achieved.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2022년도 추계학술대회
• /
• pp.570-573
• /
• 2022

본 논문에서는 신경망 모델을 적용한 몰드변압기의 보이드 결함 크기 판별에 관한 연구를 수행하였다. PCB 기반의 로고우스키 코일형 부분방전 센서를 제작하여 부분방전 신호를 측정하였고, 보이드에 의한 부분방전 결함을 모의하기 위한 PD 전극계를 제작하였다. 또한 보이드는 원통형 모양의 알루미늄 틀을 제작하여 에폭시가 경화되는 과정에서 실린지를 삽입하고 공기를 주입하여 서로다른 직경을 가지는 4개의 시편을 제작하였다. 보이드 결함 크기 판별을 위해 부분방전 전하량, 방전 펄스 수, 위상 분포의 부분방전 특성 파라미터를 추출하여 Labview 기반의 VI (Virtual Instrument)로 역전파 알고리즘을 설계하였다. 실험 결과로부터 제작된 알고리즘은 90%이상의 판별률로 결함의 직경크기를 구분할 수 있었다. 본 연구의 결과는 현장에서 PD 측정 시 몰드변압기의 유지보수 및 절연물 교체의 근거 자료로 활용될 수 있을 것으로 판단된다.

• 한국심리학회지 : 문화 및 사회문제
• /
• 제18권1호
• /
• pp.53-77
• /
• 2012

여성의 경제활동참여증가, 생활수준향상 및 가족유지비용증가, 개인적가치우선의 현상에 따라 최근 저출산현상이 더욱 심화되었으며, 이에 대한 사회적 비용 급증을 우려하여 전반적인 대응전략을 마련된 것이 바로 저출산고령사회기본계획이다. 1차에 이은 2차 기본계획은 일반가족의 양육지원과 종합적인 일가정양립지원 강화가 주요 핵심으로 이는 비단 정책뿐아니라 전방위적으로 사회전반에 걸친 변화가 수반되어야 가능한 일이다. 이 논문에서는 이러한 저출산대응정책의 실제사례를 살펴보기 위해 가족과 지역사회내 돌봄지원정책을 살펴 보았다. 가족내 자녀양육지원사업으로서 아이돌봄지원사업과 가족내 돌봄나눔에 있어 핵심요인인 남성의 자녀양육참여를 촉진하기 위한 남성대상교육, 그리고 지역내에서 가족 돌봄나눔을 실천할 수 있는 가족품앗이와 공동육아나눔터 운영을 통해 향후 저출산 정책에서 강조하고 있는 일반가족의 자녀양육지원 방향에 대한 해법을 제시하고 있다.

• 한국간호교육학회지
• /
• 제29권4호
• /
• pp.381-394
• /
• 2023

Purpose: This study aimed to develop an intentional rounding protocol to enhance the clinical competence of nursing students. Methods: An intentional rounding protocol for nursing students' clinical practice was developed following the ADDIE (Analysis, Design, Development, Implementation, and Evaluation) model. A convenient sampling method was used to select 23 junior year university nursing students during their clinical practice in adult nursing. The program evaluation included a quantitative assessment (communication and relationship efficacy, empathy, and patient safety competency) and focus group interviews. Results: The intentional rounding protocol focused on the 4Ps (pain, position, potty, and possessions) and encompassed aspects such as level of consciousness, pain management, personal care needs, intravenous injection, oxygen administration, nasogastric/nasoenteric tube care, maintenance of urine collection bags, and the identification of environmental fall risks. Nursing students performed intentional rounding at least twice a day. Following the implementation of this protocol, nursing students demonstrated a significant improvement in communication and interpersonal efficacy. The focus group interviews revealed four main themes: growth of human relationships, acquiring knowledge in and about the clinical field, becoming a nurse, and barriers in reality. Conclusion: The intentional rounding protocol has the potential to enhance nursing students' communication and interpersonal skills during clinical practice and to provide them with positive experiences in nursing clinical education. Therefore, it is recommended that this protocol be incorporated into nursing clinical practice education.

• Journal of Forest and Environmental Science
• /
• 제40권2호
• /
• pp.99-110
• /
• 2024

According to the REDD+ program, it is necessary to monitor, quantify, and report forest conditions in protected land areas. The objectives of this work were to quantify the average monthly aerial net primary productivity (ANPP_MONTH) of semi-arid Chaco Forest at Copo National Park (CNP), Santiago del Estero, Argentina, during the period 2000-2023, as well as its spatial distribution and relationship, and its use efficiency (RUE) of average monthly rainfall (AMR). The ANPP_MONTH model accounted for 90% of the seasonal variability from October to May, the average seasonal ANPP_MONTH was 145 tons of dry matter per hectare (t dm/ha), being the maximum in January with 192 t dm/ha and the minimum in May with 91 t dm/ha. The surface area covered by ANPP_MONTH exhibited a consistent positive trend from October to May (t test=15.65, p<0.01). Strong and significant direct relationships were found between ANPP_MONTH and AMRs, linear models explaining 90% and 96% of the variability, respectively. The results obtained become reference values for assessing the capacity of the forest systems to stock carbon for global warming mitigation and for monitoring and controlling their response to extreme climatic adversities. The average ANPP_MONTH reduces uncertainty when defining the thresholds to monitor and quantify ANPP and forest area, thus facilitating the detection of negative changes in land use in CNP. Such results evidence the National Parks Administration's high effectiveness for the maintenance of protected area and for the high ANPP of the FCHS of CNP in the period 2000-2023.

• Korean Journal of Radiology
• /
• 제1권1호
• /
• pp.19-24
• /
• 2000

Objective: In order to investigate the functional brain anatomy associated with verbal and visual working memory, functional magnetic resonance imaging was performed. Materials and Methods: In ten normal right handed subjects, functional MR images were obtained using a 1.5-T MR scanner and the EPI BOLD technique. An item recognition task was used for stimulation, and during the activation period of the verbal working memory task, consonant letters were used. During the activation period of the visual working memory task, symbols or diagrams were employed instead of letters. For the post-processing of images, the SPM program was used, with the threshold of significance set at p < .001. We assessed activated brain areas during the two stimulation tasks and compared the activated regions between the two tasks. Results: The prefrontal cortex and secondary visual cortex were activated bilaterally by both verbal and visual working memory tasks, and the patterns of activated signals were similar in both tasks. The superior parietal cortex was also activated by both tasks, with lateralization to the left in the verbal task, and bilaterally without lateralization in the visual task. The inferior frontal cortex, inferior parietal cortex and temporal gyrus were activated exclusively by the verbal working memory task, predominantly in the left hemisphere. Conclusion: The prefrontal cortex is activated by two stimulation tasks, and this is related to the function of the central executive. The language areas activated by the verbal working memory task may be a function of the phonological loop. Bilateral prefrontal and superior parietal cortices activated by the visual working memory task may be related to the visual maintenance of objects, representing visual working memory.

• 한국간담췌외과학회지
• /
• 제28권1호
• /
• pp.80-91
• /
• 2024

Backgrounds/Aims: Optimal intravenous fluid management during the perioperative period for patients undergoing pancreaticoduodenectomy (PD) within the framework of enhanced recovery after surgery (ERAS) is unclear. Studies have indicated that excessive total body salt and water can contribute to the development of oedema, leading to increased morbidity and extended hospital stays. This study aimed to assess the effects of an intravenous therapy regimen during postoperative day (POD) 0 to 2 in PD patients within ERAS. Methods: A retrospective interventional cohort study was conducted, and it involved all PD patients before and after implementation of ERAS (2009-2017). In the ERAS group, a targeted maintenance fluid regimen of 20 mL/kg/day with a sodium requirement of 0.5 mmoL/kg/day was administered. Outcome measures included the mmol of sodium and chloride administered, length of stay, and morbidity (postoperative pancreatic fistula, POPF; acute kidney injury, AKI; ileus). Results: The study included 169 patients, with a mean age of 64 ± 11.3 years. Following implementation of the intravenous fluid therapy protocol, there was a significant reduction in chloride and sodium loading. However, in the multivariable analysis, chloride administered (mmoL/kg) did not independently influence the length of stay; or rates of POPF, ileus, or AKI (p > 0.05). Conclusions: The findings suggested that a postoperative intravenous fluid therapy regimen did not significantly impact morbidity. Notably, there was a trend towards reduced length of stay within an increasingly comorbid patient cohort. This targeted fluid regimen appears to be safe for PD patients within the ERAS program. Further prospective research is needed to explore this area.

• 한국안전학회지
• /
• 제39권3호
• /
• pp.7-13
• /
• 2024

This study examines the physical characteristics of self-regulating heating cables caused by increased temperature and fire risk due to local degradation. A thermo hygrostat system, a convection dryer, a digital multimeter (Agilent 34465 A), NI DAQ, and the LabVIEW program were used to assess the physical properties in response to temperature fluctuations. As the temperature increases, the resistance of the self-regulating heating cable increases; however, when the critical point is exceeded, the resistance sharply decreases. A problem arises when the resistance value cannot return to its original state even though the temperature is lowered to the initial state. Moreover, when the ambient temperature rises while power is applied, the resistance value initially increases, and the flowing current decreases, maintaining a constant state. However, when the critical temperature is exceeded, the flowing current increases because of a rapid decrease in the resistance value, progressing to ignition. When the resistance value decreases because of the deterioration of one local area, the total resistance value becomes less than the initial resistance value. Therefore, the flowing current increases and an ignition problem occurs at one location where deterioration occurs. Despite the sustained flames and arcs resulting from the changes in the overall physical properties of the self-regulating heating cable and resistance variations due to local decline, the fire continued as the flowing current was lower than the operating current of the circuit breaker, failing to cut the power. In the case of self-regulating heating cables and heating wires, which are the leading causes of fires in winter, efforts are needed to ensure the need for periodic maintenance and the use of KS-certified products.

• 한국산학기술학회논문지
• /
• 제16권12호
• /
• pp.8107-8115
• /
• 2015

본 연구는 1980년대 말 신문 지면에 등장한 '전생활백화점'의 의미를 건축적으로 이해하기 위한 것이다. 전생활백화점은 판매 이외 생활에 필요한 다양한 프로그램과 서비스를 제공하는 백화점을 설명하기 위하여 나타난 용어이다. 단어 자체로 보면 '전생활'은 전(全)과 생활(生活)의 합성어로 전체 생활을 의미하므로, 구분된 생활이 있다는 것을 전제하고 있는 것이다. 따라서 근대 이후 도시와 건축에서 생활유지를 위해 필요한 공간과 건축물 등을 분류하고 구분한 지역시설로 설명될 수 있을 것이라 생각하였고, 이를 바탕으로 지역시설로 '전생활백화점'을 이해해 보고자 하였다. 지역시설의 구분체계에서 일반적으로 백화점은 3차(광역) 생활권의 시설이다. 하지만 용어가 등장한 당시 백화점의 입지와 프로그램분석을 통해 백화점이 아파트단지를 중심으로 일상생활범위 내에 위치하고 아파트에 거주하는 그들의 일상생활을 위한 공간들을 포함하고 있었음을 확인하였다. 즉 전생활의 전(全)은 1차, 2차 생활, 3차 생활의 전체를 의미하는 것으로 이해할 수 있으며, 입지적으로는 1차생활권에 위치한 3차생활 지역시설이었다. 이러한 특수한 백화점은 현재까지도 유효하기에 유의미하며 더 이상 전생활백화점이라는 용어는 별도로 사용하지 않는다.

• 한국산학기술학회논문지
• /
• 제16권12호
• /
• pp.8314-8324
• /
• 2015

본 경쟁력 있는 국방력을 유지하기 위해서는 무기체계의 지속적인 양산도 중요하지만 유지보수 및 성능개량 또한 중요한 요소로 인식되게 되었다. 방위사업청의 주도로 국내 국방획득사업이 시스템공학을 기반으로 점차 과학화로 진전되면서, 무기체계획득에서 신연구개발사업 뿐만 아니라 성능개량사업에 대해서도 효율적 관리에 관심이 집중되게 되었다. 한편 국외상업구매는 국내 국방획득사업 형태의 하나로서, 지금까지 단순 구매사업으로 취급되어 왔는데, 특히 개조 개발이 필요한 경우 문제점이 많이 있음이 인지되었다. 본 연구에서는 무기체계 성능개량 사업 중 개조 개발이 수반되는 국외상업구매 사업에 대해서도 연구개발 수준의 프로세스를 적용해야 할 필요성을 제시하고, 관련 개선 프로세스를 연구하였다. 구체적으로 개조 개발단계 획득프로세스를 시스템공학 기반에 따라 정립하고, 요구문서 작성 프로세스와 템플릿을 도출하였다. 제안된 프로세스와 템플릿의 적용을 통해 국외상업구매를 통한 무기체계 성능개량 사업에서 개조 개발에 대한 정확한 요구분석과 효율적 사업수행 및 사업목표 달성에 대한 신뢰도 향상이 기대된다.