• The KSFM Journal of Fluid Machinery
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• v.13 no.5
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• pp.43-53
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• 2010

This study investigates a design optimization of a rotating two-pass rectangular cooling channel with staggered arrays of pin-fins. The radial basis neural network method is used as an optimization technique with Reynolds-averaged Navier-Stokes analysis of fluid flow and heat transfer with shear stress transport turbulent model. The ratio of the diameter to height of the pin-fins and the ratio of the streamwise spacing between the pin-fins to height of the pin-fin are selected as design variables. The optimization problem has been defined as a minimization of the objective function, which is defined as a linear combination of heat transfer related term and friction loss related term with a weighting factor. Results are presented for streamlines, velocity vector fields, and contours of Nusselt numbers, friction coefficients, and turbulent kinetic energy. These results show how fluid flow in a two-pass square cooling channel evolves a converted secondary flows due to Coriolis force, staggered arrays of pin-fins, and a $180^{\circ}$ turn region. These results describe how the fluid flow affects surface heat transfer. The Coriolis force induces heat transfer discrepancy between leading and trailing surfaces, having higher Nusselt number on the leading surface in the second pass while having lower Nusselt number on the trailing surface. Dean vortices generated in $180^{\circ}$ turn region augment heat transfer in the turning region and in the upstream region of the second pass. As the result of optimization, in comparison with the reference geometry, thermal performance of the optimum geometry shows the improvement by 30.5%. Through the optimization, the diameter of pin-fin increased by 14.9% and the streamwise distance between pin-fins increased by 32.1%. And, the value of objective function decreased by 18.1%.

• The Korean Journal of Applied Statistics
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• v.16 no.1
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• pp.87-100
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• 2003

Most of statistical data are generated by a set of dynamic, stochastic, and simultaneous relations. An important question is how to specify statistical models so that they are consistent with the dynamic feature of those data. A general hypothesis is that the lagged effect of a change in an explanatory variable is not felt all at once at a single point in time, but The impact is distributed over a number of future points in time. In other words, current control variables are determined by a function that can be reduced to a distributed lag function of past observations. It is possible to explain the relationship between variables in different points of time and to estimate the long-run impacts of a change in a variable on another if time lag series of explanatory variables are incorporated in the model specification. In this study, distributed lag structure is applied to the domestic stock market model to capture the dynamic response of the market by exogenous shocks. The Domestic market is found more responsive to the changes in foreign market factors both in the short and the long run.

• Annals of Clinical Neurophysiology
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• v.8 no.1
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• pp.1-5
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• 2006

The head thrust maneuver is a simple bedside test of the higher frequency vestibulo-ocular reflex, which is based on Ewald's second law. It is performed by grasping the patient's head and applying a brief, small-amplitude, high-acceleration head turn, first to one side and then to the other. The patient fixates on the examiner's nose and the examiner watches for corrective rapid eye movements (saccades), which are a sign of decreased vestibular response. The "catch-up" saccades after a head thrust in one direction indicate a peripheral vestibular lesion on that side (in the labyrinth or the $8^{th}$ nerve including the root's entry zone in the brain stem). An individual pair of vertical semicircular canals can also be stimulated by turning the head to the right or left by $45^{\circ}$ and then by rotating the head in the pitch plane relative to the body. Recent studies have suggested that assessment of individual semicircular canal function by head thrust test may provide useful information for anatomical and functional details of a variety of peripheral vestibulopathies and for predicting the prognosis of vestibular neuritis. In central vestibulopathy, the head thrust test may also be valuable sign to determine dysfunction of the central pathways from individual semicircular canals and its role for the development of diverse central nystagmus.

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.1
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• pp.41-48
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• 1992

Various soil behaviors usually occurring in the geotechnical problems, such as, cutting and embankments, stability of slope, seepage, consolidations, shearing failures and liquefaction, should be predicted and analyzed in any way. An approach of these predictions may be followed by the development of the constitutive equations as first and subsequently solved by numerical methods. The purpose of this paper is develop the constitutive equation of sands uder monotonic or cyclic loadings. The constitutive equation which is based on elasto-plastic theory, modified anisotropic consolidated stress parameter by Sekiguchi et al and Pender's theory is derived. And the equation is included a new stress parameter, hardening function, Bauschinger's effects and Pender's theory. The model is later evaluated and confirmed the validity by the test data of Ottawa sand, Banwol sand Hongseong sand. The following conclustions may be drawn: 1. The consititutive equation which is based on elasto-plastic theory, modified anisotropic consolidated stress parpameter by Sekiguchi et al and Pender's theory is derived. The equation in included a new stress parameter, hardening function, Bauschinger's effect and Pender's theory. 2. For Ottawa sand, the result of the constitutive equation shows a better agreement than that of Oka et al. The result of axial strain agrees well with the tested data. However, the result of horizontal strain is little bit off for the cyclic loadings or large stress. It is thought that the deviation may be improved by considering Poisson's ratio and precise measurement of shear modulus. 3. Banwol sand is used for the strain and stress tests with different relative densitites and confining pressures. The predeicted result shows a good agreement with the tested data because the required material parameters were directly measurd and determined form this laboratory. 4. For Hongseong sand, the tests under same amplitude of cyclic deviatoric stress shows a similar result with the tested data in absolute strain. It shows the acute shape of turning point because the sine wave of input is used in the test but the serrated wave in prediction.

• Korean Institute of Interior Design Journal
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• v.21 no.5
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• pp.399-410
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• 2012

Due to development of modern medical services and economics, people raised expectation and demand about medical services from previous disease treatment to comprehensive health care covering prevention and health care. Responses of each medical facility to these social needs and the evolution of concept of medicine rapidly occur. The health examination centers are being operated with the purpose of health examination and this trend is reflected on several aspects such as the size of the facilities, function and configuration of space in health examination centers. Thus, health examination centers consisting of various space systems appear, but this trend and interpretations are lacking. Therefore, the purpose of this study is to draw trends of system through analysis of types and its evolved space systematic analysis and establish it. Analysis targets were classified into small, medium and large groups by sizes based on number of space and a total of 12 health examination centers in four for each category were selected. As research methods, functional relationship of space was examined through analysis of type in which segmentalized type tools were applied in local units. The flow diagram was established based on direction turning point and was classified into sub-flow and main-flow in local units and the systems between local units were derived. Finally, the results of this study can be summarized as the following three results. 1) The space connection system of health examination center showed four systems such as circulation, independence, continuation, and network. 2) Local type indicators and global type indicators which were evolved more from limitation of type analysis tools in existing research were derived so that more systematic analysis could be made. 3) Network system is distributed approach system and space for each function is formed around public space.

• The Journal of Korea Robotics Society
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• v.16 no.3
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• pp.250-259
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• 2021

Path planning is one of the important technologies for automated parking. It requires to plan a collision-free path considering the vehicle's kinematic constraints such as minimum turning radius or steering velocity. In a complex parking lot, Rapidly-exploring Random Tree^* (RRT^*) can be used for planning a parking path, and Reeds-Shepp or Hybrid Curvature can be applied as a tree-extension method to consider the vehicle's constraints. In this case, each of these methods may affect the computation time of planning the parking path, path-tracking error, and parking success rate. Therefore, in this study, we conduct comparative analysis of two tree-extension functions: Reeds-Shepp (RS) and Hybrid Curvature (HC), and show that HC is a more appropriate tree-extension function for parking path planning. The differences between the two functions are introduced, and their performances are compared by applying them with RRT^*. They are tested at various parking scenarios in simulation, and their advantages and disadvantages are discussed by computation time, cross-track error while tracking the path, parking success rate, and alignment error at the target parking spot. These results show that HC generates the parking path that an autonomous vehicle can track without collisions and HC allows the vehicle to park with lower alignment error than those of RS.

• Journal of Korean Society of Transportation
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• v.26 no.1
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• pp.145-153
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• 2008

Existing shortest-path algorithms mainly consider a single attribute. But traveler actually chooses a route considering not single attribute but various attributes which are synthesized travel time, route length, personal preference, etc. Therefore, to search the optimal path, these attributes are considered synthetically. In this study route searching algorithm which selects the maximum utility route using discrete choice model has developed in order to consider various attributes. Six elements which affect route choice are chosen for the route choice model and parameters of the models are estimated using survey data. A multinomial logit models are developed to design the function of route choice model. As a result, the model which has route length, delay time, the number of turning as parameter is selected based on the significance test. We use existing shortest path algorithm, which can reflect urban transportation network such as u-turn or p-turn, and apply it to the real network.

• Journal of Powder Materials
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• v.18 no.4
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• pp.378-384
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• 2011

In this research, the indium dissolution properties of the waste LCD panel powders were investigated as a function of milling time fabricated by high-energy ball milling (HEBM) process. The particle morphology of waste LCD panel powders changed from sharp and irregular shape of initial cullet to spherical shape with an increase in milling time. The particle size quickly decreased to 15 ${\mu}m$ until the first minute, then decreased gradually about 6 ${\mu}m$ with presence of agglomerated particles after 5 minutes, which increased gradually reaching a uniform size of 13 ${\mu}m$ consist of agglomerated particles after 30 minutes. The glass recovery, after dissolution, was over 99% at initial cullet, which decreased to 90.1 and 78.6% with increasing milling time of 1 and 30 minute respectively, due to a loss in remaining powder of the surface ball and jar, as well as the filter paper. The dissolution amount of indium out of the initial cullet was 208 ppm before milling, turning into 223 ppm for the mechanically milled powder after 1 minute, and nearly 146~125 ppm with further increase in milling time because of the reaction surface decrease of powders due to agglomeration. With this process, maximum dissolving indium amount (223 ppm) could be achieved at a particle size of 15 ${\mu}m$ with 1 minute of milling.

• Korea Journal of Hospital Management
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• v.8 no.4
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• pp.1-25
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• 2003

The wave of globalisation initiated by marketisation has increasingly penetrated into all sectors across the world, accordingly, the health & hospital service sector could not be made no escapes, and it currently faces the order of more marketised competition more than ever. Traditionally, the characteristic of the hospital services in the UK has considered as a model of social provision by government. However, contrary to our knowledge, the sphere of the hospital service in the UK has already been immersed in by the marketisation, in which the private actors have been embedded in order to tweak the activities of the hospital service with in the European Union. As the methodology of this research, the qualitative analysis, namely the interview with some doctors in Surgery, NHS Trusts staffs and relevant specialists in has been performed on April to May, 2003. And on the other hand, the various documents related to its service have been analysed. Thus, this paper will review the characteristics of the health service sector in the UK. In doing so, it will illuminate what would be the structural factors derived from its existing system, as a result, it will shed light on how the UK government makes an effort to resolve the problematic situation by reviewing the policy direction of Foundation Hospital proposed recently. In the next stage, it will analyse how all elements consist of the hospital management in the UK has been adjusted and be likely to be changed within Europe. More specifically focuses on how the private hospital service has been managed and related with the activities of its public hospital service-NHS Trusts. Also, under the circumstance, what private health insurance companies function will be studied. In conclusion, it will be concluded that what will be the implication of Korean hospital service market so as to correspond to globally open market by WTO. Now the UK health service system has faced a turning point of becoming more health care market internally and externally pressed by global and regional factors. Thus it is meaningful to scrutinize how a key part of social provision in the health care market system tends to adjust to globally marketised regulation.

• Science of Emotion and Sensibility
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• v.17 no.1
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• pp.29-38
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• 2014

In recent days, according as ergonomics and aesthetic engineering are important factors in the product market, there is a demand to develop automobile seat and interior designs which are focused on sensitive elements such as aesthetic and comfort features in order to satisfy the sensitive needs of consumers. To meet such demands, car seats are turning into functional and sensitive products that reflect elements of function and entertainment. According to such trends, this research is aimed to develop the illuminating car seat fabric that serve such functions as recognizing and reacting to car environments, which includes sensing over-speed, open doors, and unfastened safety belts through the illuminating car seat fabrics by optical fiber. For this purpose, basic physical properties of optical fiber are analyzed, appropriate weaving and etching technologies are applied, and the woven fabric of optical fiber for car seats are illuminating depend upon car environments. Moreover, the applicable woven fabric of optical fiber is deduced after evaluating the physical properties (such as tensile strength, heatproof, anti-fouling, washable and combustible traits) for the appropriateness of applying the woven fabric of optical fiber to car seats. For this purpose, the woven fabric of optical fiber is covered according to car seat processes; the optical fiber applied to seats is composed that it may be connected to one end of the connector linked to a LED so that it may perform functions like sensing over-speed, open doors, and unfastened safety belts; the sensed signals are transmitted to the control part, and luminescent signals are transmitted to LED.