• Journal of the Korean Institute of Landscape Architecture International Edition
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• 제2호
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• pp.185-191
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• 2004

This study dealt with the Kogi River, located in Kaizuka City, Osaka, which has experienced different improvements from the upper through the lower regions, aimed at revealing temporal relations between residents and the river, as well as probing future problems and directions regarding the river in the suburban area, by conducting a survey of local residents. The result showed that, in the upper region where nature remains in its natural state and the good water quality has been maintained, the relations between the residents and the river continued until around 1965; meanwhile in the middle region the relations have been disappearing since about 1955, and in the lower region where the stream has been repeatedly rehabilitated since 1955, there are fewer involvements of the people with the river. It also revealed that the weaker the relations between people and the river became, the larger the number of residents, even in the upper region, who became concerned over the deteriorating river environment after about 1975, and that in the middle and lower areas, about a decade earlier than in the upper area, the number of those who were aware of the environmental deterioration began to increase. Consequently, with an eye to resuming the relations between people and the river in an suburban area, their future challenges would be the space improvements depending on the environmental characteristics of the area; for example, the recovery of grassy banks for the purpose of protection in the lower region; the preservation and maintenance of many waterside woods as well as the creation of open spaces utilizing the river banks in the middle area; and throughout the whole region, the establishment of a system in which the relations between man and the river can be passed down to future generations, by utilizing the local human resources including those who know the former river landscapes or about the playing in and around the river.

• Computers and Concrete
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• 제30권1호
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• pp.19-32
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• 2022

This paper presents an investigation into the failure of RC columns under impact loadings. A numerical simulation of 19 identical RC columns subjected to single and repeated impact loadings was performed. A free-falling hammer was dropped at midspan with the same total kinetic energy input but varying mass and momentum. The specimens under the repeated impact test were struck two times at the same location. The colliding index, defined as the impact energy-momentum ratio, was proposed to explain the different impact responses under equal-energy impacts. The increase of colliding index from low to high indicates the transition of the impact response from static to dynamic and failure mode from flexure to shear. This phenomenon was more evident when the column had a greater axial load and was impacted with a high colliding index. The existence of the axial load had an inhibitory effect on the crack development and increased the shear resistance. The second impact changes the failure mode from flexural to brittle shear as found in the specimen with 20% axial load subjected to high a colliding index. Moreover, a deflection prediction equation based on the impact energy and force was limited to the low colliding index impact.

• Smart Structures and Systems
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• 제29권1호
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• pp.105-116
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• 2022

Stay cables play an essential role in cable-stayed bridges. Severe vibrations and/or harsh environment may result in cable failures. Therefore, an efficient structural health monitoring (SHM) solution for cable damage detection is necessary. This study proposes a data-driven method for immediately detecting cable damage from measured cable forces by recognizing pattern transition from the intact condition when damage occurs. In the proposed method, pattern recognition for cable damage detection is realized by time series classification (TSC) using a deep learning (DL) model, namely, the long short term memory fully convolutional network (LSTM-FCN). First, a TSC classifier is trained and validated using the cable forces (or cable force ratios) collected from intact stay cables, setting the segmented data series as input and the cable (or cable pair) ID as class labels. Subsequently, the classifier is tested using the data collected under possible damaged conditions. Finally, the cable or cable pair corresponding to the least classification accuracy is recommended as the most probable damaged cable or cable pair. A case study using measured cable forces from an in-service cable-stayed bridge shows that the cable with damage can be correctly identified using the proposed DL-TSC method. Compared with existing cable damage detection methods in the literature, the DL-TSC method requires minor data preprocessing and feature engineering and thus enables fast and convenient early detection in real applications.

• 산업경영시스템학회지
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• 제46권4호
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• pp.281-293
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• 2023

This study addresses the optimal design methodology for switching between active electronically scanned array (AESA) radar operating modes to easily select the necessary information to reduce pilots' cognitive load and physical workload in situations where diverse and complex information is continuously provided. This study presents a procedure for defining a hidden Markov chain model (HMM) for modeling operating mode changes based on time series data on the operating modes of the AESA radar used by pilots while performing mission scenarios with inherent uncertainty. Furthermore, based on a transition probability matrix (TPM) of the HMM, this study presents a mathematical programming model for proposing the optimal structural design of AESA radar operating modes considering the manipulation method of a hands on throttle-and-stick (HOTAS). Fighter pilots select and activate the menu key for an AESA radar operation mode by manipulating the HOTAS's rotary and toggle controllers. Therefore, this study presents an optimization problem to propose the optimal structural design of the menu keys so that the pilot can easily change the menu keys to suit the operational environment.

• 한국산학기술학회논문지
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• 제17권7호
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• pp.481-491
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• 2016

본 연구는 고객들에게 매력적인 관심을 끌 수 있는 고객 재방문의 요소를 알아보고 성공할 수 있는 음식점 콘셉트와 스토리텔링에 의한 고객의 재방문에 관한 연구에 대해 알아보고자 한다. 음식점 콘셉트나 광고, 음식점 인테리어도 이제는 음식점의 메뉴/서비스의 특징이나 다른 음식점과의 비교우위를 강조하던 전략에서 벗어나 이야기를 들려주는 방식으로 표현 콘셉트를 변화해야 할 것이다. 논문의 연구결과를 살펴보면, 멤버십 카드나 레스토랑을 이용하는 편리성과 같은 금전적 또는 비금전적 '전환비용'이 일시적 고객만족의 실패로 인한 레스토랑 고객들의 부정적 감정이나 낮은 만족수준을 보완해주고 레스토랑을 재방문하도록 만드는 효과가 있다고 한다. 따라서 이러한 전환비용이 고객유지에 미치는 영향을 충분히 고려한다면 효과적인 수단으로 사용할 수 있을 것이다. 레스토랑과 같은 고급 음식점에서는 음식의 맛, 고객 서비스, 음식점 분위기 등의 수준향상을 통해 방문고객의 긍정적 소비감정을 느끼게 되면 고객만족과 재방문 의도를 강화시키는 것이며, 점포 콘셉트, 물리적 환경과 같은 경험적 요소, 조명을 이용한 시각적 식감의 수준향상을 꾀하는 것도 중요하다. 또한, 긍정적 소비감정을 유발하려면 점포 콘셉트, 물리적 환경, 경험적 요소를 활용한다. 즉, 멤버십 카드, 마일리지 포인트, 고객과의 친분 등 다양한 금전적, 비금전적 마케팅 수단을 평상시 제공한다면 고객의 재방문에 긍정적인 영향을 미칠 것이다.

• 가정과삶의질연구
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• 제34권4호
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• pp.89-109
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• 2016

The purposes of this study were to analyze and understand the life of mothers rearing children with Down syndrome and to present basic data for overcoming the difficulties of those families. For these purposes, this study made use of the phenomenological analysis and approach with a qualitative research method. The subjects of this study are 4 mothers rearing children with Down syndrome who are beyond school age. The results were as follows. First, the reason why mothers with Down syndrome children went through psychological shock and horror was the social stigma due to the unusual appearance of children with Down syndrome. Second, the isolation with in the public education system was disclosed as a factor causing much sorrow and pain. Through this, we can recognize the importance of ensuring the equal right to receive education of children with Down syndrome. Third, the period which the mother experienced most shock and confusion was right after finding out about the disability that her child has. So, we can identify the importance of early intervention providing psychotherapy and rearing service to the parents. Fourth, the crucial factor that relieved pain and pressure from mothers was social support including family. Therefore, the social support system for mothers with Down syndrome children has to be developed and strengthened. Fifth, the crucial factor that made mother grow up during rearing experience was the reestablishment of cognition about the desired role of mothers. Through this, we can identify the importance of the mental transition process to independent thinking.

• 한국대기환경학회지
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• 제20권5호
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• pp.593-601
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• 2004

In this study, we are going to compare the chemical composition of the precipitation that falls in the Dangjin and Anmyon-do areas by analyzing the water soluble components (anion and cation). We also examined the effects of seasonal change and regional difference in those data sets. The [$NO_3\;^- \;+\;SO_4\;^{2-}$] at 49.2${\mu}$eq/l is 67% of the total anion of 73.1${\mu}$eq/l, while that of [$NH_4\;^+\;+\;Ca^{2+}$] at 37.7${\mu}$eq/l is 62% of the cation in Dangjin area. Also, the [$NO_3\;^-\;+\;SO_4\;^{2-}$] concentration of 151.8 (${\mu}$eq/l) is 62% for the total anion of 143.5 (${\mu}$eq/l), and the [$NH_4\;^+\;+\;Ca^{2+}$] concentration of 119.7 (${\mu}$eq/l) is 47% for the cation of 254.3 (${\mu}$eq/l) in Anmyon-do area. The ion composition ratio is shown for the order by 22% of $SO_4\;^{2-}$, 20.8% of $NH_4\;^+$ and 15.4% of $Cl^-$ that is the sum of 58.7% for the total ion composition in Dangjin area, and is the order by 33.8% of $NH_4\;^+$, 16.3% of $SO_4\;^{2-}$ and 11.1% of $Cl^-$ in Anmyon-do area. Furthermore, We predicted that even areas which were previously clean will get acid rain if there is large scale construction there or nearby.

• 한국정보통신학회논문지
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• 제20권2호
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• pp.289-298
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• 2016

지난 10년간 공인인증서 인프라(NPKI-National Public Key Infrastructure) 기반의 우리나라 안전 인터넷 거래 환경은 급속하게 발전하여 왔지만, 한편으로는 폐쇄적인 방식으로 동작하는 NPKI 기반의 인터넷 거래 환경으로 인해 개방성과 호환성 측면에서 여러 가지 문제점들도 노출되어 왔다. 인터넷 거래의 활성화를 위해서는 이러란 문제점들이 가까운 시일 내에 해결될 필요가 있고, 웹 기반 안전 인터넷 거래의 국제 표준인 SSL/TLS 기반으로의 전환이 해결책이 될 수 있을 것으로 받아들여지고 있다. SSL/TLS 기반의 안전 인터넷 거래로의 전환은 현재의 NPKI 기반의 인터넷 거래의 장점을 잘 유지하면서 추진되어야 할 것이다. 본 논문의 주된 목적은 NPKI기반의 인터넷 거래와 SSL/TLS 기반의 인터넷 거래의 장단점을 구체적으로 비교분석하여, SSL/TLS 기반의 NPKI 구현의 기본 아이디어를 파악하는 데 있다. 그런 다음 분석 결과를 바탕으로 현재의 NPKI 기반의 인터넷 거래의 장점을 잘 유지하면서 NPKI 기반 인터넷 거래 환경을 SSL/TLS 기반의 인터넷 거래 환경으로 전환하기 위한 방안을 제시하고자 한다.

• Geomechanics and Engineering
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• 제11권1호
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• pp.141-160
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• 2016

This study elucidates the uplift behaviors of the straight-sided and belled shafts. The field uplift load tests were carried out on 18 straight-sided and 15 belled shafts at the three collapsible loess sites under an arid environment on the Loess Plateau in Northwest China. Both the site conditions and the load tests were documented comprehensively. In general, the uplift load-displacement curves of the straight-sided and belled shafts approximately exhibited an initial linear, a curvilinear transition, and a final linear region, but did not provide a well defined peak or asymptotic value of the load, and therefore their uplift resistances should be interpreted from the load test results using an appropriate criterion. Nine representative uplift resistance interpretation criteria were used to define the "interpreted failure load" for each of the load tests, and all of these interpreted uplift resistances were normalized by the failure threshold, $T_{L2}$, obtained using the $L_1-L_2$ method. These load test data were compared statistically and graphically. For the straight-sided and belled shafts, the normalized uplift load-displacement curves were respectively established by the plots that related the mean interpreted uplift resistance ratio against the mean displacement at the corresponding interpreted criteria, and the comparisons of the normalized load-displacement curves were made. Specific recommendations for the designs of uplift belled and straight-sided shafts in the loess were given, in terms of both capacity and displacement.

• 한국물환경학회지
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• 제27권5호
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• pp.634-645
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• 2011

A newly developed rainwater harvesting (RWH) system reliability model is evaluated for roof area of buildings in Haeundae District of Busan. RWH system is used to supply water for toilet flushing, back garden irrigation, and air cooling. This model is portable because it is based on a non-parametric precipitation generation algorithm using a markov chain. Precipitation occurrence is simulated using transition probabilities derived for each day of the year based on the historical probability of wet and dry day state changes. Precipitation amounts are selected from a matrix of historical values within a moving 30 day window that is centered on the target day. Then, the reliability of RWH system is determined for catchment area and tank volume ranges using synthetic precipitation data. As a result, the synthetic rainfall data well reproduced the characteristics of precipitation in Busan. Also the reliabilities of RWH system for each of demands were computed to high values. Furthermore, for study area using the RWH system, reduction efficiencies for rooftop runoff inputs to the sewer system and potable water demand are evaluated for 23%, 53%, respectively.