• Title/Summary/Keyword: challenging problems

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A comparative study on rapid seismic risk prioritization for reinforced concrete buildings in Antalya, Türkiye

  • Engin Kepenek;Kasim A. Korkmaz;Ziya Gencel
    • Computers and Concrete
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    • v.31 no.3
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    • pp.185-195
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    • 2023
  • Antalya is located south part of minor Asia, one of the biggest cities in Türkiye. As a result of population growth and vast migration to Antalya, many parts of the city that were not suitable for construction due to its geological conditions have become urban areas, and most of these urban areas are full of poorly engineered buildings. Poor engineering has been combined with unplanned urbanization, that causes utter vulnerability to disasters in Antalya. When an earthquake-prone city, Antalya faces with an earthquake risk, fear arises in society. To overcome this problem, it has become necessary to investigate the building stock, expressed in hundreds of thousands, in a fast and reliable way and then perform an urban transformation to create the perception of structural safety. However, the excessive building stock, labor, and economic problems made the implementation stage challenging and revealed the necessity of finding alternative solutions in the field. The present study presents a novel approach for assessment and model based on a rapid visual inspection method to transform areas under earthquake risk in Türkiye. The approach aimed to rank the interventions for decision-making mechanisms by making comparisons in the scale hierarchy. In the present study, to investigate the proposed approach, over 26,000 buildings were examined in Antalya, which is the fifth largest city in Türkiye that has a population of over 2.5 Million. In the results of the study, the risk classification was defined in the framework of building, block, street, neighborhood, and district scales.

Development of roadheader performance prediction model and review of machine specification (로드헤더 장비사양 검토 및 굴착효율 예측 모델 개발)

  • Jae Hoon Jung;Ju Hyi Yim;Jae Won Lee;Han Byul Kang;Do Hoon Kim;Young Jin Shin
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.25 no.3
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    • pp.221-243
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    • 2023
  • The use of roadheaders has been increasing to mitigate the problems of noise and vibration during tunneling operations in urban area. Since lack of experience of roadheader for hard rock, the selection of appropriate machines and the evaluation of cutting rates have been challenging. Currently, empirical models developed overseas are commonly used to evaluate cutting rates, but their effectiveness has not been verified for domestic rocks. In this paper, a comprehensive literature review was conducted to assess the rock cutting force, cutterhead capacity, and cutting rate to select the appropriate machine and evaluate its performance. The cutterhead capacity was reviewed based on the literature results for the site. Furthermore, a new empirical model and simplified method for predicting cutting rates were proposed through data analysis in relation to operation time and rock strength, and compared with those of the conventional model from the manufacturer. The results show good agreement for high strength range upper 80 MPa of uniaxial compressive strength.

ESTIMATING COSTS DURING THE INITIAL STAGE OF CONCEPTUAL PLANNING FOR PUBLIC ROAD PROJECTS: CASE-BASED REASONING APPROACH

  • Seokjin Choi;Donghoon Yeo;Seung H. Han
    • International conference on construction engineering and project management
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    • 2009.05a
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    • pp.1183-1188
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    • 2009
  • Estimating project costs during the early stage of conceptual planning is very important when deciding whether to approve the project and allocate an appropriate budget. However, due to greater uncertainties involved in a project, it is challenging to estimate costs during this initial stage within a reasonable tolerance. This paper attempts to develop a cost-estimate model for public road projects under these circumstances and limitations. In the conceptual planning stage of a road project, there is only limited information for cost estimation, for example, such input data as total length of the route, origin and destination, number of lanes, general geographic characteristics of the route, and other basic attributes. This implies that the model should individuate suitable but restricted information without considering detailed features such as quantity of earthwork and a detailed route of a given condition. With these limited facts, this paper applies a case-based reasoning (CBR) method to solve a new problem by deriving similar past problems, which in turn is used to estimate the cost of a given project based on best-fitted previous cases. To develop a CBR cost-estimate model, the authors classified 8 representative variables, including project type, the number of lanes, total length, road design grades, etc. Then, we developed the CBR model, primarily by using 180 actual cases of public road projects, procured over the last decade. With the CBR model, it was found that the degree of error in estimation can be reasonably reduced, to below approximately 30% compared to the final costs estimated upon the completion of detailed design.

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Oblique Axis Hypothenar Free Flaps: Tips for Harvesting Larger Flaps with Minimal Donor Site Morbidity

  • Sang Ho Oh;Jae In Chung
    • Archives of Plastic Surgery
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    • v.50 no.3
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    • pp.279-287
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    • 2023
  • Background Hypothenar free flaps (HTFFs) have been widely used for reconstructing palmar defects. Although previous anatomical and clinical studies of HTFF have been conducted, this technique still has some limitations. In this study, we describe some tips for large flap design that allows for easy harvesting of HTFFs with minimal donor site morbidity. Methods A total of 14 HTFF for hand defect reconstruction were recorded. The oblique flap was designed in the proximal HT area following relaxed skin tension line along the axis between fourth web space and 10 mm ulnar side of pisiform. A flap pedicle includes one or two perforators with ulnar digital artery and HT branch of basilic vein. In addition, innervated HTFF can be harvested with a branch of ulnar digital nerve. Electronic medical records were reviewed to obtain data on patients' information, operative details, and follow-up period. In addition, surgical outcome score was obtained from the patient, up to 10 points, at the last follow-up. Results Mean harvest time was 46 minutes, and two perforators were included in 10 cases. The mean flap area was 10.84 cm2. There were no problems such as donor site depression, scar contracture, keloids, wound dehiscence, numbness or neuroma pain at donor sites, and hypersensitivity or cold intolerance at flap site, either functionally or aesthetically. Conclusion Palmar defect reconstruction is challenging for hand surgeons. However, large HTFF can be harvested without complications using the oblique axis HTFF technique. We believe our surgical tips increase utility of HTFF for palmar defect reconstruction.

Improving the Security Policy Based on Data Value for Defense Innovation with Science and Technology (과학기술 중심 국방혁신을 위한 데이터 가치 기반 보안정책 발전 방향)

  • Heungsoon Park
    • Convergence Security Journal
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    • v.23 no.1
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    • pp.109-115
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    • 2023
  • The future outlook for defense faces various and challenging environments such as the acceleration of uncertainty in the global security landscape and limitations in domestic social and economic conditions. In response, the Ministry of National Defense seeks to address the problems and threats through defense innovation based on scientific and technological advancements such as artificial intelligence, drones, and robots. To introduce advanced AI-based technology, it is essential to integrate and utilize data on IT environments such as cloud and 5G. However, existing traditional security policies face difficulties in data sharing and utilization due to mainly system-oriented security policies and uniform security measures. This study proposes a paradigm shift to a data value-based security policy based on theoretical background on data valuation and life-cycle management. Through this, it is expected to facilitate the implementation of scientific and technological innovations for national defense based on data-based task activation and new technology introduction.

Safety Class Design with Bitbricks (비트브릭을 활용한 안전 수업 설계)

  • Park, Minyoung;Shin, Seungki
    • 한국정보교육학회:학술대회논문집
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    • 2021.08a
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    • pp.303-308
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    • 2021
  • In this study, we intended to present a class design plan that combines safety education and software education, which are very important in the school field, but are considered necessary for change. In order to realize safety education centered on indirect experience, the 12th class plan was devised as a "Smart Safety Commuter Road Production Project" using a physical computing tool called Bitbrick. Based on the 12th city's class plan, qualitative research was conducted with interviews with a total of five teachers, showing both the effectiveness and problems of applying them to the class. The effectiveness is that unlike conventional delivery-type safety education, indirect experience-oriented safety education centered on real-life situations is possible, and it can be expected that procedural thinking skills can be developed along with stimulating interest. However, the problem has been shown that the process of implementing the direct situation can be challenging and that even activities can be more efficient than group activities.

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Evaluating the accuracy of mass scaling method in non-linear quasi-static finite element analysis of RC structures

  • A. Yeganeh-Salman;M. Lezgy-Nazargah
    • Structural Engineering and Mechanics
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    • v.85 no.4
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    • pp.485-500
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    • 2023
  • The non-linear static analysis of reinforced concrete (RC) structures using the three-dimensional (3D) finite element method is a time-consuming and challenging task. Moreover, this type of analysis encounters numerical problems such as the lack of convergence of results in the stages of growth and propagation of cracks in the structure. The time integration analysis along with the mass scaling (MS) technique is usually used to overcome these limitations. Despite the use of this method in the 3D finite element analysis of RC structures, a comprehensive study has not been conducted so far to assess the effects of the MS method on the accuracy of results. This study aims to evaluate the accuracy of the MS method in the non-linear quasi-static finite element analysis of RC structures. To this aim, different types of RC structures were simulated using the finite element approach based on the implicit time integration method and the mass scaling technique. The influences of effective parameters of the MS method (i.e., the allowable values of increase in the mass of the RC structure, the relationship between the duration of the applied load and fundamental vibration period of the RC structure, and the pattern of applied loads) on the accuracy of the simulated results were investigated. The accuracy of numerical simulation results has been evaluated through comparison with existing experimental data. The results of this study show that the achievement of accurate structural responses in the implicit time integration analyses using the MS method involves the appropriate selection of the effective parameters of the MS method.

Representation of Curl Exaggeration, Cohesion, Adhesion and Stiffness in Wet Curly Hair

  • Jong-Hyun Kim
    • Journal of the Korea Society of Computer and Information
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    • v.28 no.10
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    • pp.77-84
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    • 2023
  • Simulating the cohesion and stiffness of wet hair or fur in physics-based simulations is one of the most challenging problems. Wet hair or fur is characterized by bunching and stiffening at the ends, a phenomenon that can be seen in wet animal fur or hair. In addition, when wet hair interacts with a solid, adhesion occurs, but this problem becomes difficult to solve due to the different distribution and balance of forces in curly hair. In traditional methods, wet hair is represented by hand or by using static hairstyles to represent wet curls and hair. However, how to depict the details of wet curly hair has not been actively researched. In this paper, we propose a new algorithm to efficiently model the curl exaggeration, cohesion, adhesion, and stiffness of wet curly hair. The proposed method efficiently simulates cohesion and integrates stiffness constraints with curl dynamics to reliably control hair elasticity.

The Concept of Health Systems Science and Educational Needs in the Korean Context (의료시스템과학의 개념과 교육 필요성 고찰)

  • Eunbae B. Yang;Danbi Lee;Jong Tae Lee
    • Korean Medical Education Review
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    • v.25 no.3
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    • pp.192-197
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    • 2023
  • Physicians should be able to address health-related issues of patients and populations from a multidimensional perspective. Therefore, medical schools have a social responsibility to develop and implement curricula that enable trainees to acquire the competencies needed to improve all aspects of patient care and healthcare delivery. This study explored the concept of health systems science concept as the third pillar of medical education (the other two are basic science and clinical medicine) in the Korean context, as well as related educational needs. The theoretical foundation of health systems science is the biopsychosocial conceptual model, which emphasizes the biological, psychological, and social factors surrounding patients. We concluded that the three domains (core functional, foundational, linking) and 12 subcategories of health systems science proposed by the Association of American Medical Colleges could be applied to Korean medical education. Health systems science education must be emphasized to solve the various healthcare problems facing Korea today and to train physicians to provide medical services in line with society's needs. Introducing a health systems science curriculum will be challenging in the Korean medical environment, which has traditionally emphasized basic science and clinical medical education. Health systems science education should begin in the basic medical education phase, where physicians' professional identity is formed, and continue through graduate medical education. It is essential to understand related educational needs, develop curricular content, conduct faculty development programs, and provide financial resources for the development of an integrated curriculum.

Convolutional Autoencoder based Stress Detection using Soft Voting (소프트 보팅을 이용한 합성곱 오토인코더 기반 스트레스 탐지)

  • Eun Bin Choi;Soo Hyung Kim
    • Smart Media Journal
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    • v.12 no.11
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    • pp.1-9
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    • 2023
  • Stress is a significant issue in modern society, often triggered by external or internal factors that are difficult to manage. When high stress persists over a long term, it can develop into a chronic condition, negatively impacting health and overall well-being. However, it is challenging for individuals experiencing chronic stress to recognize their condition, making early detection and management crucial. Using biosignals measured from wearable devices to detect stress could lead to more effective management. However, there are two main problems with using biosignals: first, manually extracting features from these signals can introduce bias, and second, the performance of classification models can vary greatly depending on the subject of the experiment. This paper proposes a model that reduces bias using convo utional autoencoders, which can represent the key features of data, and enhances generalizability by employing soft voting, a method of ensemble learning, to minimize performance variability. To verify the generalization performance of the model, we evaluate it using LOSO cross-validation method. The model proposed in this paper has demonstrated superior accuracy compared to previous studies using the WESAD dataset.

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