• Wind and Structures
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• 제21권6호
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• pp.625-639
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• 2015

Monopiles have been most widely used for supporting offshore wind turbines (OWTs) in shallow water areas. However, multi-member lattice-type structures such as jackets and tripods are also considered good alternatives to monopile foundations for relatively deep water areas with depth ranging from 25-50 m owing to their technical and economic feasibility. Moreover, jacket structures have been popular in the oil and gas industry for a long time. However, several unsolved technical issues still persist in the utilization of multi-member lattice-type supporting structures for OWTs; these problems include pile-soil-interaction (PSI) effects, realization of dynamically stable designs to avoid resonances, and quick and safe installation in remote areas. In this study, the effects of PSI on the dynamic properties of bottom-fixed OWTs, including monopile-, tripod- and jacket-supported OWTs, were investigated intensively. The tower and substructure were modeled using conventional beam elements with added mass, and pile foundations were modeled with beam and nonlinear spring elements. The effects of PSI on the dynamic properties of the structure were evaluated using Monte Carlo simulation considering the load amplitude, scouring depth, and the uncertainties in soil properties.

• Structural Engineering and Mechanics
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• 제61권3호
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• pp.359-370
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• 2017

This study presents a particle swarm optimization algorithm integrated with weighted particle concept and improved fly-back technique. The rationale behind this integration is to utilize the affirmative properties of these new terms to improve the search capability of the standard particle swarm optimizer. Improved fly-back technique introduced in this study can be a proper alternative for widely used penalty functions to handle existing constraints. This technique emphasizes the role of the weighted particle on escaping from trapping into local optimum(s) by utilizing a recursive procedure. On the other hand, it guaranties the feasibility of the final solution by rejecting infeasible solutions throughout the optimization process. Additionally, in contrast with penalty method, the improved fly-back technique does not contain any adjustable terms, thus it does not inflict any extra ad hoc parameters to the main optimizer algorithm. The improved fly-back approach, as independent unit, can easily be integrated with other optimizers to handle the constraints. Consequently, to evaluate the performance of the proposed method on solving the truss weight minimization problems with discrete variables, several benchmark examples taken from the technical literature are examined using the presented method. The results obtained are comparatively reported through proper graphs and tables. Based on the results acquired in this study, it can be stated that the proposed method (integrated particle swarm optimizer, iPSO) is competitive with other metaheuristic algorithms in solving this class of truss optimization problems.

• Nuclear Engineering and Technology
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• 제49권2호
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• pp.295-305
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• 2017

This paper reviews current status of the unified approach known as integrated safety assessment (ISA), as well as the associated SCAIS (simulation codes system for ISA) computer platform. These constitute a proposal, which is the result of collaborative action among the Nuclear Safety Council (CSN), University of Madrid (UPM), and NFQ Solutions S.L, aiming to allow independent regulatory verification of industry quantitative risk assessments. The content elaborates on discussions of the classical treatment of time in conventional probabilistic safety assessment (PSA) sequences and states important conclusions that can be used to avoid systematic and unacceptable underestimation of the failure exceedance frequencies. The unified ISA method meets this challenge by coupling deterministic and probabilistic mutual influences. The feasibility of the approach is illustrated with some examples of its application to a real size plant.

• Asian Pacific Journal of Cancer Prevention
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• 제15권13호
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• pp.5111-5116
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• 2014

Computed Tomography Colonography (CTC) is a medical imaging technology used in identifying polyps and colon cancer masses in the large intestine. The technique has evolved a great deal since its invention and has become a routine diagnostic procedure in Western countries due to its non invasiveness and ease of use. The objective of our study was to explore the possibility of CTC application in Indian hospitals. This paper gives an overview of the procedure and its commercial viability. The explanation begins with the domain aspects from gastroenterologist perspective, the new way of thinking in polyp classification, the technical components of CTC procedure, and how engineering solutions have helped clinicians in solving the complexities involved in colon diagnosis. The colon cancer statistics in India and the results of single institution study we carried out with retrospective data is explained. By considering the increasing number of patients developing colon malignancies, the practicality of CTC in Indian hospitals is discussed. This paper does not reveal any technical aspects (algorithms) of engineering solutions implemented in CTC.

• The Journal of Korean Institute for Practical Engineering Education
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• 제2권2호
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• pp.113-119
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• 2010

The objective of this study is to perform the systematic research and to develop programs for improving the teaching abilities of vocational teachers, so that they can cope with the variant educational condition in accordance with the change of paradigm. Especially vocational teachers who engage in technical education can acquire new knowledge and techniques as well as grasp the trend of the new technologies required in industrial fields. In this study preliminary research for the capabilities of vocational teachers was held and the feasibility was investigated. Upon these investigations the essential elements for the improvement of vocational teachers' capabilities were derived. These will be used as preliminary data for operating curricula.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제26권6호
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• pp.581-588
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• 2015

In this paper, we researched that setting standard for RSC(Radar Cross Section) of naval surface ship could be determined and considered in various ways on ship's survivability, technical building feasibility, operation and so on. This study presented fundamental capacity on anti-ship missile, radar, flight and so no and the procedure to set of target/standards for RSC. The RCS standards is good at setting low as low as to improve survivability aspect, but because we should consider effect, technical limit, cost etc, this paper analyzed necessary elements to set standard than to suggest specific number and suggested procedure to set standars according to suggest the boundary of RCS.

• KEPCO Journal on Electric Power and Energy
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• 제2권2호
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• pp.317-325
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• 2016

In recent years, the U.S, Japan, Europe and other developed countries are strategically developing technologies in order to prepare for paradigm shift affecting the electric power industry in a preemptive way. In particular, a chance for new business models and innovation in the electric power industry would rapidly increase with convergence of various technologies including Information and communication technologies. This study gathered up the theories and methodologies, and sorted out emerging technologies for the electric power industry with those theories. In order to find the emerging technologies, first, we identified the possible key issues of the electric power industry in the future using four mining techniques such as STEEP. Second, we drew agenda related with each key issue. Third, we organized candidates of the emerging technologies for solving the agenda and set the priority after evaluating the possibility of technical innovation and business. Finally, we selected the top fourteen of emerging technologies and assessed their feasibility. This study has a methodological significance because the emerging technologies were developed with a market-oriented approach rather than technical-push one that has been primarily used in another studies. The results of this study are able to be used in establishment of technology policy and R&D planning in the electric power industry.

• Journal of Gastric Cancer
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• 제17권3호
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• pp.193-203
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• 2017

The implementation of national cancer screening has increased the detection rates of early gastric cancer (EGC) in Korea. Since the successful introduction of laparoscopic gastrectomy for gastric cancer in the early 1990s, this technique has demonstrated improved short-term outcomes without compromising long-term oncologic results. It is associated with reduced pain, shorter hospitalization, reduced morbidity rates, better cosmetic outcomes, and equivalent mortality rates as those for open surgery. Laparoscopic gastrectomy improves patients' quality of life (QOL) and provides favorable prognosis. Single-incision laparoscopic gastrectomy (SILG) is one extremely minimally invasive method, theoretically offering improved cosmetic results, less postoperative pain, and earlier recovery after surgery than conventional multiport laparoscopic gastrectomy. In this context, SILG is thought to be an optimal method to promote and maximize patients' QOL in the acute postoperative phase. However, the technical difficulties of this procedure have limited its use. Since the first report describing single-incision distal gastrectomy in 2011, only 16 studies to date have evaluated SILG. Most of these studies have focused on the technical feasibility and safety of SILG because its long-term outcomes have not been reported. This article reviews the advantages and limitations of SILG.

• Journal of Biosystems Engineering
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• 제20권1호
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• pp.22-35
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• 1995

Pepper is the most important horticultural plant in Korean farm. Pepper harvesting has been known to be the most difficult process in pepper cultivation so that demand for mechanization is strong. In a research to develop a pepper harvesting machine performance and capacity of the harvester should be determined based on both economical feasibility and machine design concept. In order to accomplish an economical analysis of the pepper harvester, a mathematical model for comparing manual harvesting cost to machine harvest cost was developed. Validity of the model depends on the data used in the model. Economical information for the model variables was acquired from the result of farm survey on pepper cultivation technique and economics of pepper farmer. Technical information on pepper harvester were also collected through literature review and analyzed. Based on the economical analysis and synthesis of the technical information on pepper harvesters, its performance and capacity were determined. The operating performances of the harvester such as cutting, conveying, flipping, pepper removing and post-processing (sorting) were determined. Daisy capacity of the machine was determined to be 0.41 ha. A pepper harvester with the suggested capacity was economically feasible if the price of pepper harvester, pepper recovery ratio and service life of harvester were about 6 million won, 80%, and 4 years, respectively.

• Journal of Korean Society on Water Environment
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• 제39권1호
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• pp.76-86
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• 2023

We are on the verge of paradigm shift for the design and operation of our urban water systems from treatment- and efficiency-based to recirculation- and sustainability-based. One of the most frequently suggested alternatives to embody this paradigm shift is to decentralize the currently highly centralized urban water infrastructure. However, claims for water infrastructure decentralization are often criticized due to poor economic feasibility, unstable performance, and unprofessional operation and maintenance. The current study critically reviews the literature to discuss the technical advancement needs to overcome such challenges. Firstly, decentralized water infrastructure was briefly defined and the rationale for the proposal of its introduction to the next-generation urban water systems was laid down. The main discussion focused on the following water technologies, which require special attention when working with decentralized water infrastructure: i) material collection, storage, and transport; ii) easily scalable water treatment; iii) sensor, information, and communications; and iv) system optimization. The principles, current development status, and challenges were discussed for each of the water technologies. The discussion on the water technologies has enabled the identification of future research needs for their application to the next-generation urban water systems which will be designed following decentralized water infrastructure. This paper will significantly improve the current understanding on water infrastructure decentralization and provides insight on future direction of water technology development.