• 한국산학기술학회논문지
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• 제20권3호
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• pp.465-469
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• 2019

본 논문에서는 콘크리트 바이브레이터에 Slotless BLDC (Brush Less Direct Current) 모터를 적용하기 위해 BLDC 모터의 토크 및 역기전력 식을 기반으로 하여 설계를 한다. 모터의 길이와 직경의 사이즈가 주어져 있으므로 중요한 파라미터는 공극자속밀도이다. 자기회로의 간략화를 통하여 공극자속밀도를 계산 하였으며, 토크, 역기전력 및 공극자속밀도 식을 기반으로 기초설계를 진행하여 모터의 형상을 결정 하였다. 이후 모터의 고정자의 외경 및 내경, 스택 길이, 속도를 고정값으로 설정한 후 모터의 직경 및 두께를 변수로 지정하여 유한요소법을 이용한 시뮬레이션을 통해 상세설계를 진행하였으며, THD(Total Harmonic Distortion)값이 작으면서 목표 토크 값 이상의 형상을 설계 및 시뮬레이션을 진행하였다.

• 한국가족복지학
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• 제57호
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• pp.183-215
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• 2017

본 논문은 돌봄민주주의 관점에서 중앙정부의 보육정책을 규범적 접근으로 분석했다. 저출산 고령화로 인한 돌봄공백이 신사회 위험으로 등장하면서 경제성장 중심에서 돌봄가치 중심으로의 패러다임 전환이 필요하다는 사회적 인식이 이루어졌다. 하지만 돌봄윤리가 개별 정책에 어떤 방식으로 반영되어야 하는가에 대한 구체적인 정책연구는 많이 이루어지지 못해왔다. 이에돌봄민주주의 관점의 '자유', '평등', '정의' 가치를 적용해서 보육정책을 분석하고 새로운 정책지향을 제시하고자 했다. 분석결과는 다음과 같다. 먼저, 자유 관점에서, 현재 보육정책은 자유선택의 제약으로 인해 공공성과 사회연대성이 담보되지 못하고 있다. 둘째, 평등관점에서 성별및 소득불평등으로 인한 계층화는 인종과 세대의 축이 더해지면서 더욱 복잡하고 다층적인 불평등을 초래했으며, 사적 돌봄의 악순환이 나타나고 있다. 셋째, 정의관점에서 과거로부터 축적되어 온 부정의는 조정을 통해 교정되지 못하면서 구조적 불평등이 오히려 심화되는 것으로 나타난다.

• 한국프랜차이즈경영연구
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• 제11권1호
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• pp.31-44
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• 2020

Purpose: The baby boomers and the millennials, who make up the largest share of the market, are showing the gap in their differentiated cultural styles. The purpose of this study is to study the consumption propensity and purchasing determinants of the baby boomers generation and the millennials generation, which have become a very important key pillar in shaping the market based on the cultural dimension model theory of h(=>H)opstead, and to identify the difference Research design, data, and methodology: In order to verify the research hypotheses, The data was collected from the baby boomers and the millennials using online questionnaires. The pre-test was conducted from October 10 to 12, 2019, and the main survey was conducted from October 15 to 25. A total of 230 copies were recalled, and the final 219 copies were used for the final analysis. Results: The consumption propensity between the baby boomers and the millennials differed in resource saving purchase propensity and impulse buying propensity. The baby boomers showed higher resource saving purchase propensity than the millennials, while the millennials showed higher impulse buying propensity. There was a difference in the determinants to purchasing only in the evaluation factor. Results of gender differences by generation, baby boomers differed in their planned purchase propensity, and women were higher. The millennials generation differed in resource saving purchase propensity and awareness propensity for others, all higher in men. In determinants to purchasing, the baby boomers did not differ in gender, and the millennials did differ in product factors. A canonical correlations analysis of the relationship between the baby boomers and the millennials showed a significant relationship between consumption propensity and determinants to purchasing. Also, the baby boomer generation has the biggest link between impulse buying propensity and evaluation factor. The millennials generation showed the biggest link between resource saving purchase and product factors. Conclusions: This study compared consumption propensity and determinants to purchasing of baby boomers and millennials on the basis of Hopstead's cultural dimension model theory to identify differences between generations, presenting practical and theoretical implications for establishing a correct understanding and specific marketing strategy among generation.

• Journal of Preventive Medicine and Public Health
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• 제55권5호
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• pp.436-443
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• 2022

Objectives: Previous studies have reported that self-neglect, which may be a sign of elder abuse, can result in suicide among older adults. The signs of self-neglect and its impact on the risk of suicide may differ by gender. Thus, this study explored the association between self-neglect and suicide risk in older Korean adults and examined the potential moderating effect of gender on this relationship. Methods: Data were collected from 356 Korean adults aged 65 or older through an online survey. Multiple regression analysis was used to test the research hypothesis. First, the associations between 4 sub-dimensions of self-neglect (i.e., daily life management issues, personal hygiene issues, financial management issues, and relational issues) and suicidal ideation were examined. Then, the moderating effect of gender on these relationships was investigated by including interaction terms. Results: Self-neglect was significantly associated with suicidal ideation in older adults. Aspects of self-neglect related to daily life management and relational factors were key predictors of suicidal ideation. Gender significantly moderated the effect of the relational dimension of self-neglect on suicidal ideation. The relational dimension of self-neglect was more strongly associated with suicidal ideation in older women than in older men. Conclusions: The findings suggest the importance of screening older adults with signs of self-neglect for suicide risk. Special attention should be paid to older women who experience relational issues as a high-risk group for suicidal ideation. Public programs and support systems should be established to improve daily life management and promote social relationships among older adults.

• 한국융합학회논문지
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• 제13권2호
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• pp.303-312
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• 2022

이 연구에서는 원격대학원생 콘텐츠 구성요소에 대한 중요도-수행도 분석(IPA)을 하였다. 이를 위해 J대학 원격대학원생 221명을 대상으로 온라인 설문조사를 한 결과 다음과 같은 결과를 얻었다. 첫째, 콘텐츠 구성요소의 영역별 중요도는 학습 내용, 상호작용, 교수-학습 전략, 평가의 순으로, 수행도는 교수-학습 전략, 상호작용, 평가, 학습내용의 순으로 나타났다. 둘째, 콘텐츠 구성요소 4가지 영역, 즉 학습내용, 교수-학습 전략, 상호작용, 평가 영역 모두 중요도와 수행도 간에 유의미한 차이가 있는 것으로 나타났다. 중요도-수행도 분석(IPA)은 영역별 및 항목별 두 차원에서 실시하였는데 그 결과는 다음과 같다. 학습내용은 유지관리 영역으로, 교수-학습 전략과 상호작용은 중점개선 영역으로, 평가 영역은 과잉투자 영역으로 밝혀졌다. 이 연구 결과는 원격대학원 콘텐츠의 현재를 진단하고 그에 기초하여 앞으로 개선해야 할 점이 무엇인가를 가늠하는 데 기초자료로 활용할 수 있을 것이다.

• Geomechanics and Engineering
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• 제32권3호
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• pp.255-270
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• 2023

One of the main parameters that affect the design of suction caisson-supported offshore structures is uplift behavior. Pull-out of suction caissons is profoundly utilized as the offshore wind turbine foundations accompany by a tensile resistance that is a function of a complex interaction between the caisson dimensions, geometry, wall roughness, soil type, load history, pull-out rate, and many other parameters. In this paper, a parametric study using a 3-D finite element model (FEM) of a single offshore suction caisson (SOSC) surrounded by saturated soil is performed to examine the effect of some key factors on the tensile resistance of the suction bucket foundation. Among the aforementioned parameters, caisson geometry and uplift loading as well as the difference between the tensile resistance and suction pressure on the behavior of the soil-foundation system including tensile capacity are investigated. For this purpose, a full model including 3-D suction caisson, soil, and soil-structure interaction (SSI) is developed in Abaqus based on the u-p formulation accounting for soil displacement (u) and pore pressure, P.The dynamic responses of foundations are compared and validated with the known results from the literature. The paper has focused on the effect of geometry change of 3-D SOSC to present the soil-structure interaction and the tensile capacity. Different 3-D caisson models such as triangular, pentagonal, hexagonal, and octagonal are employed. It is observed that regardless of the caisson geometry, by increasing the uplift loading rate, the tensile resistance increases. More specifically, it is found that the resistance to pull-out of the cylinder is higher than the other geometries and this geometry is the optimum one for designing caissons.

• International Journal of Computer Science & Network Security
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• 제23권3호
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• pp.110-122
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• 2023

Over the last few decades, various innovative technologies have emerged that have significantly contributed to making life easier for humans. Various information and communication technologies (ITCs) have emerged as a result of the global technological revolution, including big data, IoT, 4G and 5G networks, cloud computing, mobile computing, and artificial intelligence. These technologies have been adopted in urban planning and development, which gave rise to the concept of smart cities in the 1990s. A smart city is a type of city that uses ITCs to exchange and share information to enhance the quality of services for its citizens. With the global population increasing at unprecedented levels, cities are overwhelmed with a myriad of challenges, such as the energy crisis, environmental pollution, sanitation and sewage challenges, and water quality issues, and therefore, have become a convergence point of economic, social, and environmental risks. The concept of a smart city is a multidisciplinary, unified approach that has been adopted by governments and municipalities worldwide to overcome these challenges. Though challenging, this transformation is essential for cities with differing technological and social features, which all have the potential to determine the success or failure of the digital transformation of cities into smart cities. In recent years, researchers, businesses, and the government have all turned their attention to the emerging field of smart cities. Accordingly, this paper aims to represent a thorough understanding of the movement toward smart cities. The key themes identified are smart city definitions and concepts, smart city dimensions, and smart city architecture of different layers. Furthermore, this article discusses the challenges and some examples of smart cities.

• Structural Engineering and Mechanics
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• 제81권1호
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• pp.81-91
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• 2022

The effects of interaction between concrete-gypsum interface and edge crack on the failure behavior of the specimens in senicircular bend (SCB) test were studied in the laboratory and also simulated numerically using the discrete element method. Some quarter circular specimens of gypsum and concrete with 5 cm radii and hieghts were separately prepared. Then the semicircular testing specimens were made by attaching one gypsum and one concrete sample to one another using a special glue and one edge crack is produced (in the interface) by do not using the glue in that part of the interface. The tensile strengths of concrete and gypsum samples were separately measured as 2.2 MPa and 1.3 MPa, respectively. during all testing performances a constant loading rate of 0.005 mm/s were stablished. The proposed testing method showed that the mechanism of failure and fracture in the brittle materials were mostly governed by the dimensions and number of discontinuities. The fracture toughnesses of the SCB samples were related to the fracture patterns during the failure processes of these specimens. The tensile behaviour of edge notch was related to the number of induced tensile cracks which were increased by decreasing the joint length. The fracture toughness of samples was constant by increasing the joint length. The failure process and fracture pattern in the notched semi-circular bending specimens were similar for both methods used in this study (i.e., the laboratory tests and the simulation procedure using the particle flow code (PFC2D)).

• 품질경영학회지
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• 제51권2호
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• pp.155-170
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• 2023

Purpose: Nowadays, the risk assessment system is widely used in many industrial and public areas to reduce the possible risks. The system is used to determine the priorities of the government quality assurance works in Defense Agency for Technology and Quality. However, as the risk assessment system is used for other purposes, there are some items that need improvement, and in this study, we propose improvement plans by benchmarking the risk assessment systems of other institutions. Methods: In this paper, first, the procedures of risk assessment system used in many industrial sites were reviewed, and how each institution specialized and applied the system. Afterwards, by benchmarking various risk assessment systems, an improvement plan on how to operate the risk assessment system in the case of government quality assurance for centrally procured military supplies was presented, and practical application cases were presented to prove the usefulness of the improvement plan. Results: The proposed risk assessment system differs from the existing system in five major aspects. First, inputs, outputs, and key performance indicators were specified from the systematic point of view. Second, risk analysis was analyzed in four dimensions: probability of occurrence, impact, detection difficulty. Third, risk mitigation measures were classified, control, transfer, and sharing. Fourth, the risk mitigation measures were realized through document verification, product verification, process verification, and quality system evaluation. Finally, risk mitigation measures were implemented and the effectiveness of the risk mitigation measures was evaluated through effectiveness evaluation. Conclusions: In order for the risk assessment procedure proposed in this study to be applied to actual work, it is necessary to obtain the consent of the person involved in the work due to the increased time for risk identification and preparation of the government quality assurance log, and a change in the information system that performs the actual work is required. Therefore, the authors of this study plan to actively perform internal seminar presentations and work improvement suggestions to apply these research outputs to actual work.

• Smart Structures and Systems
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• 제30권5호
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• pp.479-500
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• 2022

In this study, a new type of isolation bearing is proposed by combining S-shaped steel plate dampers (SSDs) with a spherical steel bearing, and the seismic control effect of a five-span standard high-speed railway bridge is investigated. The advantages of the proposed S-shaped steel damping friction bearing (SSDFB) are that it cannot only lengthen the structural periods, dissipate the seismic energy, but also prevent bridge unseating due to the restraint effectiveness of SSDs in the large relative displacements between the girders and piers. This study first presents a detailed description and working principle of the SSDFB. Then, mechanical modeling of the SSDFB was derived to fundamentally define its cyclic behavior and obtain key mechanical parameters. The numerical model of the SSDFB's critical component SSD was verified by comparing it with the experimental results. After that, parameter studies of the dimensions and number of SSDs, the friction coefficient, and the gap length of the SSDFBs were conducted. Finally, the longitudinal seismic responses of the bridge with SSDFBs were compared with the bridge with spherical bearing and spherical bearing with strengthened shear keys. The results showed that the SSDFB can not only significantly mitigate the shear force responses and residual displacement in bridge substructures but also can effectively reduce girder displacement and prevent bridge unseating, at a cost of inelastic deformation of the SSDs, which is easy to replace. In conclusion, the SSDFB is expected to be a cost-effective option with both multi-stage energy dissipation and restraint capacity, making it particularly suitable for seismic isolation application to high-speed railway bridges.