• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.6
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• pp.39-47
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• 2021

Reduction effect of the spread of odorant and fine dust through windbreak trees can be predicted through numerical analysis. However, there is a disadvantage that a large space and destructive experiments must be carried out each time to calculate the aerodynamic coefficient of the tree. In order to overcome these shortcomings, In this study, we aimed to estimate the aerodynamic coefficient (C₀, C₁, C₂) by using image processing. Thuja occidentalis, which can be used as windbreak were used as the material. The leaf area index was estimated from the leaf area ratio using image processing with leaf weight, and the optical porosity was calculated through image processing of photos taken from the side while removing the leaves step-by-step. Correlation analysis was conducted with the aerodynamic coefficient of Thuja occidentalis calculated from the wind tunnel test and leaf area index and optical porosity calculated from the image analysis. The aerodynamic coefficient showed positive and negative correlations with the leaf area index and optical porosity, respectively. The results showed that the possibility of estimating the aerodynamic coefficient using image processing.

• Steel and Composite Structures
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• v.30 no.6
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• pp.535-550
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• 2019

Prestressed concrete (PC) bridges using corrugated steel webbing have emerged as one of the most promising forms of steel-concrete composite bridge. However, their long-term behavior is not well understood, especially in the case of large-span bridges. In order to study the time-dependent performance, a large three-span PC bridge with corrugated steel webbing was compared to a similar conventional PC bridge to examine their respective time-dependent characteristics. In addition, a three-dimensional finite element method with step-by-step time integration that takes into account cantilever construction procedures was used to predict long-term behaviors such as deflection, stress distribution and prestressing loss. These predictions were based upon four well-established empirical creep prediction models. PC bridges with a corrugated steel web were observed to have a better long-term performance relative to conventional PC bridges. In particular, it is noted that the pre-cambering for PC bridges with a corrugated steel web could be smaller than that of conventional PC bridges. The ratio of side-to-mid span has great influence on the long-term deformation of PC bridges with a corrugated steel web, and it is suggested that the design value should be between 0.4 and 0.6. However, the different creep prediction models still showed a weak homogeneity, thus, the further experimental research and the development of health monitoring systems are required to further progress our understanding of the long-term behavior of PC bridges with corrugated steel webbing.

• The Southeast Asian review
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• v.20 no.2
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• pp.1-29
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• 2010

In 1835, quickly after the Cambodian king Ang Chan died, Vietnamese emperor Minh Mang started to proceed his ambition to grab the territory of Cambodia. As the first step, he stationed big forces led by Truong Minh Giang in Phnom Phen, and appointed the Ang Chan's second daughter, Mei, as the successor of her father but with the humble title of Chan Lap Quan Chu, or the Prefecture sovereign of Cambodia. This article discusses the ways how the Vietnamese leaders manipulated the status of the Cambodian queen with each step of protection, assimilation, and finally a rupture. The author seeks for Vietnamese own theory of annexation in the process. In doing so, the author claims that Vietnamese tough policy of annexation was closely interwoven with the unequal relationship between the Vietnamese emperors and the Cambodian queen, i. e. men and woman. The first chapter discusses how and why the second daughter was chosen, and what in reality the status of the queen was under the protection of Vietnamese general Truong Minh Giang. Second chapter shows how much Mei was bullied by the Vietnamese. She was kidnapped to Vietnam, and was even regarded by the Cambodian people that she became the 'lover' or the 'concubine' of the general Truong Minh Giang. Third chapter deals with Vietnam's retreat forced by the Cambodian resistance together with the Thai intervention, and discusses how much Vietnam tried to maintain its authority over Cambodia through the queen Mei. Cambodia, in the 19th century, was a experimental place for the 'mission of civilization' from the side of Vietnam. Mei was a main character in this period from the beginning to the end. The conclusion of this article stresses that the desire of Vietnam ('civilized') to assimilate Cambodia ('barbarious') was strengthened by the psychology of the male master (Vietnam) to domesticate the female subject (Cambodia). The relationship between Vietnam and Cambodia was not only political but also gender oriented. In this epic, the existence of the queen Mei should be regarded as an important key to understanding of the Vietnamese theory for the annexation of Cambodia.

• The Journal of the Society of Stroke on Korean Medicine
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• v.14 no.1
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• pp.80-89
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• 2013

■ Objectives The aim of study is to analyze the change of gait pattern by arm sling in a hemiplegic patient. ■ Methods We analyzed the change of gait pattern under three conditions using Treadmill Gait analysis equipment(Zebris Co.Ltd FDM-T) First, the patient didn't have arm sling on her upper limb, second, the patient have arm sling on her affected upper limb, third, patient have arm sling on her unaffected upper limb. ■ Results In terms of spatiotemporal gait values, swing phase, step time, step length of unaffected lower limb increased. Furthermore, stride time and stride length also increased when the patient had arm sling on her unaffected upper limb. In terms of displacement of Center of pressure(CoP), anterior/posterior position and lateral symmetry of CoP increased. Furthermore, lateral symmetry of decreased when the patient had arm sling on her affected upper limb. ■ Conclusion Arm sling applied on affected side would be advantage to gait improvement in hemiplegic patients.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.2
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• pp.117-126
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• 2011

RSA-CRT algorithm is widely used to improve the performance of RSA algorithm. However, it is also vulnerable to side channel attacks like as general RSA. One of the power attacks on RSA-CRT, proposed by Boer et al., is a power analysis which utilizes reduction steps of RSA-CRT algorithm with equidistant chosen messages, called as ECMPA(Equidistant Chosen Messages Power Analysis) or MRED(Modular Reduction on Equidistant Data) analysis. This method is to find reduction output value r=xmodp which has the same equidistant patterns as equidistant messages. One can easily compute secret prime p from exposure of r. However, the result of analysis from a reduction step in [5] is remarkably different in our experiment from what Boer expected in [5]. Especially, we found that there are Ghost key patterns depending on the selection of attack bits and selected reduction algorithms. Thus, in this paper we propose several Ghost key patterns unknown to us until now, then we suggest enhanced and detailed analyzing methods.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.5
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• pp.45-49
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• 2010

The automotive industry has shown a growing interest in tube hydroforming during the past years. The advantages of hydroforming (less thinning, a more efficient manufacturing process, etc.) can, for instance, be combined with the high strength of extra high strength steels, which are usually less formable, to produce structural automotive components which exhibit lower weight and improved service performance. Design and production of tubular components require knowledge about tube material and forming behavior during hydroforming and how the hydroforming operation itself should be controlled. These issues are studied analytically in the present paper. In this study, the whole process of rear sub-frame parts development by tube hydroforming using AA6061 material is presented. At the part design stage, it requires feasibility study and process design aided by CAE (Computer Aided Engineering) to confirm hydroformability in details. Effects of parameters such as internal pressure, axial feeding and geometry shape in automotive rear sub-frame by hydroforming process were carefully investigated. Overall possibility of hydroformable rear sub-frame parts could be examined by cross sectional analyses. Moreover, it is essential to ensure the formability of tube material on every forming step such as pre-bending and hydroforming. In addition, all the components of prototyping tool are designed and interference with press is examined from the point of geometry and thinning.

• Korea-Australia Rheology Journal
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• v.14 no.4
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• pp.189-201
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• 2002

The interaction between hydrophobically modified hydroxyethyl cellulose (hmHEC), containing approximately 1 wt% side-alkyl chains of $C_{16}$, and an anionic sodium dodecyl sulphate (SDS) surfactant was investigated. For a semi-dilute solution of 0.5 wt% hmHEC, the previously observed behaviour of a maximum in solution viscosity at intermediate SDS concentrations, followed by a drop at higher SDS concentrations, until above the cmc of surfactant when the solution resembles that of the unsubstituted polymer, was confirmed. Additionally, a two-phase region containing a hydrogel phase and a water-like supernatant was found at low SDS concentrations up to 0.2 wt%, a concentration which is akin to the critical association concentration, cac, of SDS in the presence of hmHEC. Above this concentration, SDS molecules bind strongly to form mixed micellar aggregates with the polymer alkyl side-chains, thus strengthening the network junctions, resulting in the observed increase in viscosity and elastic modulus of the solution. The shear behaviour of this polymer-surfactant complex during steady and step stress experiments was examined In great detail. Between SDS concentrations of 0.2 and 0.25 wt%, the shear viscosity of the hmHEC-polymer complex network undergoes shear-induced thickening, followed by a two-stage shear-induced fracture or break-up of the network. The thickening is thought to be due to structural rearrangement, causing the network of flexible polymers to expand, enabling some polymer hydrophobic groups to be converted from intra- to inter-chain associations. At higher applied stress, a partial local break-up of the network occurs, while at even higher stress, above the critical or network yield stress, a complete fracture of the network into small microgel-like units, Is believed to occur. This second network rupture is progressive with time of shear and no steady state in viscosity was observed even after 300 s. The structure which was reformed after the cessation of shear is found to be significantly different from the original state.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.10
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• pp.4339-4347
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• 2014

Purpose: This study aimed at exploring treatment delay (TD) among cancer patients in China with an attempt to develop a practical methodology facilitating frontline Chinese clinicians in promoting earlier cancer diagnosis and treatment. Materials and Methods: The study comprised framework development, qualitative interviews and paired factor rating. Framework development utilized systematic literature review, soft systems thinking and consensus groups. Qualitative interviews employed a checklist of open questions soliciting information about all the domains included the framework from cancer patients drawn via stratified randomized sampling of inpatients at 10 hospitals in Hefei, China. Paired factor rating used a self-developed computer aid and the interviewed patients as referring cases to weigh the relative importance of the factors listed in the framework in terms of their contributions to specific components of total delay (TD). Results: a) A conceptual framework was proposed consisting of a 6-step path to TD and 36 category determinants. b) A total of 227 patients were interviewed; their TD was 267.3 mean or 108 median days ranging from 0 to 2475 days; average appraisal, illness, behavioral, preparation and treatment delay accounted for 52.1%, 9.4%, 0.30%, 8.8% and 29.4% of the TD respectively. Individual side factors were rated substantially more important than environmental side factors (60% vs. 40%); most influential TD factors included cancer symptoms, overall health, family relations and knowledge about cancer and health. Conclusions: The framework proposed together with the interviewing and rating approaches used provide a potential new methodology for understanding cancer patients' TD and promoting earlier cancer treatment.

• The KSFM Journal of Fluid Machinery
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• v.19 no.5
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• pp.50-60
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• 2016

A design methodology of the modeled test facility to conserve an injection performance of a passive safety injection system is proposed. This safety injection system is composed of a core makeup tank and a safety injection tank. Individual tanks are connected with pressure balance line on the top side and injection line on the bottom side. It is important to conserve the scaled initial injection flow rate and total injection time since this system can be operated by small gravity head without any active pumps. Differential pressure distribution of the injection line induced by the gravity head is determined by the vertical length and elevation of each tank. However, the total injection time is adjustable by the flow resistance coefficient of the injection line. The scaling methodology for the tank and flow resistance coefficient is suggested. A key point of this test facility design is a scaling analysis for the flow resistance coefficient. The scaling analysis proposed on this paper is based on the volume scaling law with the same vertical length to the prototype and can be extended to a model with a reduced vertical length. A set of passive injection test were performed for the tanks with the same volume and the different length. The test results on the initial flow rate and total injection time showed the almost same injection characteristics and they were in good agreement with the design values.

• Physical Therapy Korea
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• v.3 no.2
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• pp.55-76
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• 1996

The objective of this study was to identify the immediate effects of the short leg brace on the weight bearing distribution and gait patterns of hemiplegic patients. The subjects of this study were 18 hemiplegic patients who had been hospitalized or visited out-patient department of Rehabilitation Hospital, Yonsei University College of Medicine, from January 5, 1996 through March 23, 1996. PLS(Posterior Leaf Spring) on and off changes in gait patterns were measured using ink foot print as well as by recording weight bearing distribution using a limb load monitor. The data were analyzed by the correlation and paired t-test. The findings were as follows: 1. Eighteen subjects were more weighted on the affected leg when PLS was put off(42.74%) than on(40.08%). 2. The defference in gait patterns between PLS on and off was statistically significant, with an increase in step length by 1.7cm on the involved side; a decrease in foot angle by 4.41 degree on the involved side; and a narrowing of base of support by 1.46cm when PLS were off. In conclusion, this study showed that PLS did not affect the weight bearing distribution and gait patterns of hemiplegic patients. Since, the evaluation method used in this study has limitations in regard to temporal distance gait values. Further studies are required to numerous experiments for subject and extensive study.