• Psychiatry investigation
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• 제15권12호
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• pp.1154-1161
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• 2018

Objective The present study aimed to investigate relationship among cognitive factors (working memory and processing speed) and fluid reasoning (Gf) in psychiatric patients using a standardized clinical tool. Methods We included the responses of 115 heterogeneous patients who were diagnosed with the MINI-Plus 5.0 and WAIS-IV/WMS-IV was administered. For our analysis, structured equation modeling (SEM) was conducted to evaluate which cognitive variables are closely related to the Gf. Results The results showed that the visual working memory was the strongest predictor of the Gf compared to other cognitive factors. Conclusion Processing speed was capable of predicting the Gf, when visual working memory was controlled. The inter-relationship among the Gf and other cognitive factors and its clinical implications were further discussed.

• 동력기계공학회지
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• 제2권3호
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• pp.21-26
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• 1998

Numerical simulations for various fluid flows require enormous computing time during iterations. In order to solve this problem, several techniques have been proposed. A SOR method is one of the effective methods for solving elliptic equations. However, it is very difficult to find the optimum relaxation factor, the value of this factor for practical problems used to be estimated on the basis of expertise. In this paper, the implication of the relaxation factor are translated into fuzzy control rules on the basis of the expertise of numerical analysers, and fuzzy controller incorporated into a numerical algorithm. From two cases of study, Poisson equation and cavity flow problem, we confirmed the possibility of computational acceleration with fuzzy logic and qualitative reasoning in numerical simulations. Numerical experiments with the fuzzy controller resulted in generating a good performance.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 춘계학술대회 논문집
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• pp.194-197
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• 2004

In the tube hydroforming process, a tube is placed into the die cavity and the ends of the tube are sealed by fixing the axial cylinder piston into the ends. Then the tube is pressurized with a hydraulic fluid and simultaneously the axial cylinders move to feed the material into the expansion zone. Therefore, the quantitative relationship between process parameters such as internal pressure and feeding amount and hydroformabillity, is hard to establish because of their high complexity and many unknown factors. In this study, the empirical and the quantitative relationship between process parameters and hydroformabillity are analyzed by fuzzy rules. Fuzzy expert system is an advanced expert system which uses fuzzy rule and approximate reasoning. Many process parameters are converted to the quantitative relationship by use of approximate reasoning of fuzzy expert system. The comparison between experimentally measured hydroformabillity from hydroforming experiments and the predicted values by fuzzy expert system shows a good agreement.

• 한국영재학회:학술대회논문집
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• 한국영재학회 2003년도 춘계학술대회
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• pp.137-138
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• 2003

Understanding how and why people differ is a fundamental, if distant, goal of research efforts to bridge psychological and biological levels of analysis. General fluid intelligence (gF) is a major dimension of individual differences and refers to reasoning and novel problemsolving ability. A conceptual integration of evidence from cognitive (behavioral) and anatomical studies suggeststhat gF should covary with both task performance and neural activity in specific brain systems when specific cognitive demands are present, with the neural activity mediating the relation between gF and performance. Direct investigation of this possibility will be a critical step toward a mechanistic model of human intelligence. In turn, a mechanistic model might suggest ways to enhance gF through targeted behavioral or neurobiological intervent ions, We formed two different groups as subjects based on their scholarly attainments. Each group consists of 20 volunteers(aged 16-17 years, right-handed males) from the National Gifted School and a local high school respectively. To test whether individual differences in general intelligence are mediated at a neural level, we first assessed intellectual characteristics in 40 subjects using standard intelligence tests (Raven's Advanced Progressive Matrices, Wechsler Adult Intelligence Scale, Torrance Tests of Creative Thinking) administered outside of the MR scanner. We then used functional magnetic resonance imaging (fMRl) to measure task-related brain activity as participants performed three different kinds of computerized reasoning tasks that were intended to activate the relevant neural systems. To examine the difference of neural activity according to discrepancy in general intelligence, we compared the brain activity of both extreme groups (each, n=10) of the participants based on the standard intelligence test scores. In contrast to the common expectation, there was no significant difference of brain region involved in high-g tasks between both groups. Random effect analysis exhibited that lateral prefrontal, anterior cingulate and parietal cortex are associated with gF. Despite very different task contents in the three high-g-low-g contrasts, recruitment of multiple regions is markedly similar in each case, However, on the task with high 9F correlations, the Prodigy group, (intelligence rank: >99%) showed higher task-related neural activity in several brain regions. These results suggest that the relationship between gF and brain activity should be stronger under high-g conditions than low-g conditions.

• 산업공학
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• 제21권4호
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• pp.411-417
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• 2008

An impeller is a type of high-speed rotor that is used to compress or transfer fluid under high-speed and pressure at high temperatures. The impeller is composed of an axial hub and several blades attached along the hub. The weight and shape of an impeller must be balanced, because their imbalances can cause noise and vibration, which can lead to the breakage of the impeller blades during operation. Thus, the hub and blades of an impeller are commonly machined in a 5-axis NC machine to obtain qualified surfaces. The impeller machining strategy or process plan can not be easily obtained due to the complex, overlapped and twisted shapes of impeller blades. Skillful machining process planners may generate appropriate machining strategies based on their experiences and floor data. However, in practice most shop floor data for the impeller machining is not well-structured such that it does not effectively provide a process planner with information for machining strategies and/or process plans. This paper reports the development of a case-based machining strategy support system (CBMS) that employs case-based reasoning to obtain the machining strategy of an impeller by using the existing machining strategies of the shop floor. The CBMS generates impeller machining strategies through a stepwise reasoning process considering the similarity features between the blade shapes and machining regions. A case study is provided to demonstrate that CBMS can generate useful machining strategies facilitating process planners. The developed system can simulate the tool paths of impeller machining and runs on the web.

• International Journal of Fluid Machinery and Systems
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• 제9권1호
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• pp.17-27
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• 2016

Researches on the mechanism of surging and the surge behaviors in the systems of pumps, or fans or compressors, and the effects of flow-paths had been initiated and had made a great progress in Japan in the decades from the nineteen-forties to the nineteen-sixties. In 1947, the essential cause of the surges, i.e., self-excited oscillation nature of the flow-system, was discovered analytically by Professor Sumiji Fujii of Tokyo University, and most of the characteristic behaviors of the phenomena had been explained clearly. Successive studies by many other Japanese researchers continued to prove experimentally the mechanism, to extend the analytical studies, and to attempt preventing surge occurrence, etc. in the following two decades. The historical information on the early surge studies could be helpful to some concerned people. At the same time, the basic and plain ways of discussions and reasoning about the phenomena in the pioneering researches could give us much to be learned even in the present time of high-power computing systems. Regrettably, many of the original research works have been published only in Japanese. The present review introduces very briefly the situations in memories of the pioneering researchers and engineers.

• 대한예방한의학회지
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• 제4권1호
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• pp.122-131
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• 2000

This dissertation is try to figure out why chestnut belongs to kidney channel, from the viewpoint of five elements theory. After studying chestnut's property, flavor, channel tropism, main cure ability, prescriptions, shape, sweet, and prohibitions, I came to the following results. 1. Property of chestnut is warm and has no toxicity, so it is less related than kidney property. 2. Flavor of chestnut is salty and sweet, so it has some relation to kidney and spleen properties. 3. Channel tropism of chestnut enters mainly into kidney channel, and then spleen and stomach channels. 4. Chestnut controls kidney function of storing the essence of life, determining the condition of bone and marrow, conduction water metabolism, affecting reasoning activity, and controls activity of nine openings of body. It also has effects on functions of spleen, intestines and stomach. 5. Prescriptions including chestnut is similar to that of human brain, it is possible to reason out that chestnut has some relation to human brain. 7. As flavor of chestnut flower is similar to that of spermatic fluid, so it has som relation to kidney property. 8. As chestnut has property of blocking qi and it causes spleen, stomach and colon system to be confused, so it is suggested that persons with weakende spleen and stomach be not allowed to take in.

• 아동학회지
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• 제37권6호
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• pp.107-117
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• 2016

Objective: This study examined the construct validity of K-WPPSI-IV. Factor structures of the structures of the K-WPPSI-IV full scale as well as primary index scales for two age ranges (2 years, 6 months to 3 years, 11 months; 4 years to 7 years, 7 months) were examined. Methods: Data were collected from 1,700 children aged 2 years, 6 months to 7 years, 7 months during the K-WPPSI-IV standardization. Confirmatory factor analyses were conducted using the K-WPPSI-IV subtest performances with maximum likelihood estimation using Amos 18. Results: First, the three-factor model (verbal comprehension, visual spatial, and working memory) fitted best for the younger age range. However, the five-factor model (verbal comprehension, visual spatial, fluid reasoning, working memory, and processing speed) fitted best for the older age range. Residuals suggest the presence of two nested subfactors within the verbal comprehension factor (broad/expressive and focused/simple). Second, the confirmatory factor analysis on primary index subtests identified factors that account for the intercorrelations among the reduced sets of primary index subtests. Conclusion: The findings showed that the theoretical structures of WPPSI-IV subtests were confirmed within K-WPPSI-IV.

• Nuclear Engineering and Technology
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• 제47권4호
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• pp.398-406
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• 2015

In this study, R-123 flow boiling experiments were carried out to investigate the effects of nanoparticle deposition on heater surfaces on flow critical heat flux (CHF) and boiling heat transfer. It is known that CHF enhancement by nanoparticles results from porous structures that are very similar to layers of Chalk River unidentified deposit formed on nuclear fuel rod surfaces during the reactor operation period. Although previous studies have investigated the surface effects through surface modifications, most studies are limited to pool boiling conditions, and therefore, the effects of porous surfaces on flow boiling heat transfer are still unclear. In addition, there have been only few reports on suppression of wetting for decoupled approaches of reasoning. In this study, bare and $Al_2O_3$ nanoparticle-coated surfaces were prepared for the study experiments. The CHF of each surface was measured with different mass fluxes of $1,600kg/m^2s$, $1,800kg/m^2s$, $2,100kg/m^2s$, $2,400kg/m^2s$, and $2,600kg/m^2s$. The nanoparticle-coated tube showed CHF enhancement up to 17% at a mass flux of $2,400kg/m^2s$ compared with the bare tube. The factors for CHF enhancement are related to the enhanced rewetting process derived from capillary action through porous structures built-up by nanoparticles while suppressing relative wettability effects between two sample surfaces as a highly wettable R-123 refrigerant was used as a working fluid.

• 대한기계학회논문집B
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• 제38권9호
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• pp.731-737
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• 2014

와류실은 압축된 공기를 이용하여 고온과 저온 가스로 분리할 수 있는 단순한 장치로, 차세대 새로운 열교환기로 각광받고 있으나, 와류실 내부에서 발행하는 물리적 유동특성에 대해 아직까지 많이 알려지지 않았다. 본 연구에서는 온도 분리 현상을 조사하기 위해 실험 및 수치해석을 수행하였다. 공급 압력에 따른 온도 변화를 측정하기 위하여 다수의 압력 및 온도 센서를 사용하였으며, CFD 기법을 적용하여 3차원 비정상 압축성 유동장을 조사하였다. 연구를 통해 온도 분리 현상은 점성일과 밀접한 관계가 있는 공급 압력과 와류실의 직경에 영향을 받았으며, 와류실에서 발생하는 온도분리 현상은 압력구배파의 개념으로 확증할 수 없었다.