• Journal of the Korean Society of Industry Convergence
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• v.9 no.1
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• pp.29-35
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• 2006

The population of Daegu, the third biggest city in Korea, is two point six million. Daegu is known as a basin or a city where it is not only too hot in summer but also too cold in winter. Recently with redevelopment apartment house boom, a 40-story or more apartment complexes are under construction near Shin-cheon and Dondaegu-ro, the south-north axis of Daegu. It is necessary to raise several points about blocking a road of the wind by high-rise apartment buildings and apartment complexes. As a kind of the green policy, Daegu enlarge the distance between apartment building by reconstructing low-rise apartment into high-rise and impose a duty of a green space on the ground by making a parking zone into an underground. Through this process, apartment complexes changed from a '一'shape to a '口'shape. It increases heat island phenomenon of a city by blocking a road of the wind that comes from Shin-cheon and Dondaegu-ro. To circulate the polluted air of Daegu basin, we need local wind. There are four effective measures. 1) Throw three greens into one in the center of the road at the north side in the same way of the south side of Dongdaegu-ro, 2) reflect the information of roads of the wind including heights, spaces and directions of buildings, 3) steer clear of a high-rise buildings and development apartment house constructions, and 4)select a city for benchmarking to be the environmental capital.

• Journal of the Korean Society of Industry Convergence
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• v.18 no.2
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• pp.99-109
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• 2015

This study proposes a new approach to analyze the impedance and the elasticity of a serial chain of spring-damper system, areal-time collision-free trajectory generation algorithm is proposed. The reference points on a trajectory connected by the spring-damper system have a mechanism for self-position adjustment to solve a collision problem by the impedance, and the local adjustment of each reference point is propagated through the elasticity to a real robot at the end of the spring-damper system. As a result, the overall trajectory consisting of the reference points becomes free of collision with environmental obstacles and efficient having the shortest distance as possible. In this process,, the reference points connected by the spring-damper system take role of virtual robot as global guidance for a real robot, and a cooperative is carried out by the system of robots. A control technology is proposed to implement for mobile robot.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.11
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• pp.2737-2753
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• 2013

In this study, we propose a novel salient object detection strategy based on regional contrast and relative spatial compactness. Our algorithm consists of four basic steps. First, we learn color names offline using the probabilistic latent semantic analysis (PLSA) model to find the mapping between basic color names and pixel values. The color names can be used for image segmentation and region description. Second, image pixels are assigned to special color names according to their values, forming different color clusters. The saliency measure for every cluster is evaluated by its spatial compactness relative to other clusters rather than by the intra variance of the cluster alone. Third, every cluster is divided into local regions that are described with color name descriptors. The regional contrast is evaluated by computing the color distance between different regions in the entire image. Last, the final saliency map is constructed by incorporating the color cluster's spatial compactness measure and the corresponding regional contrast. Experiments show that our algorithm outperforms several existing salient object detection methods with higher precision and better recall rates when evaluated using public datasets.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.6
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• pp.877-883
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• 1987

A new improved inviscid separation model to calculate the mean flow past circular cylinders is proposed. The wake region is modeled by a pair of vortex sheets which emerge from the separation points and are allowed to move freely with the local stream. The vortex strength assumes a constant value for some initial distance which is related to the pressure drag and gradually decreases to zero as the sheet moves farther away from the body. This vorticity distribution automatically takes care of the length parameter which has been one of the deficiencies in the existing models. The procedure is tested against various experimental data and the agreement is quite good for both sub and super-critical regimes. The comparison with an existing model is also given.

• Journal of Power System Engineering
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• v.20 no.1
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• pp.69-74
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• 2016

The local heat transfer and pressure drops of developed turbulent flows in the convergent channels with square cross-sectional areas along the streamwise distance have been investigated experimentally. Four different parallel angled ribs (a = $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, and $90^{\circ}$) are placed to the one sided wall only, respectively. The ribbed walls are manufactured with a fixed rib height (e)=10 mm and the ratio of rib spacing (p) to height (e) = 10. The measurement was run within the range of Reynolds numbers from 22,000 to 79,000. The result shows that the increases in the Nusselt numbers for the flow attack angles can be seen in the order of $30^{\circ}$, $45^{\circ}$, $60^{\circ}$ and $90^{\circ}$.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.1
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• pp.49-63
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• 2008

The objectives of this research were to evaluate the pressurized/the main inlet water flowrate ratio which have been used as the most important parameter for operating the pump diffusion mixer until now, to suggest the alternative operating parameter and the relating criteria if the flowrate ratio was not inadequate. For the objectives of this research, computational fluid dynamics (CFD) simulation was conducted for 21 cases of flowrate ratio in full-scaled pump diffusion mixer. From the results of CFD simulation, the local velocity gradient values were calculated in each case in order to analyze the simulation results in more detail. For verifying CFD simulation, wet test was conducted. The wet test was to measure the factual coagulant dispersion distribution at a distance of 5.4m from deflector. From both results of CFD simulation and wet test, flowrate ratio was inadequate as operating parameter or criteria, on the other hand the pressurized/the main inlet velocity ratio(dimensionless) was useful in predicting the performance of pump diffusion mixer. Also, the injected coagulant could be dispersed evenly in overall cross section on the condition that pressurized/the main inlet velocity ratio(dimensionless) is over at least 20.

• Transactions of Materials Processing
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• v.19 no.8
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• pp.508-516
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• 2010

Thickening process in sheet metal forming is being increased to improve the strength as well as to reduce manufacturing process such as welding. This process can make it possible to obtain part locally thicker than that of initial sheet thickness. In this study, design method for manufacturing the component which has double sinks with local thickened wall is proposed. Deep drawing and upsetting processes are applied in order to form double sinks and thicken its walls. Used material is SPHC440 with the thickness of 2.0mm and initial blank size is determined on the basis of the final product. Distance between the center of double sinks and first drawing ratio to avoid fracture are the most significant factors during deep drawing. FE-analysis is implemented in order to determine the appropriate values. Progressive die is designed based on the proposed method and FE-analysis. As a result of experiment, locally thickened component can be manufactured, which has double sinks with the thickness about 3mm at the corner and wall.

• Journal of Korean Neurosurgical Society
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• v.37 no.3
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• pp.197-200
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• 2005

Objective: Ultrasound can be used in the treatment of large intracerebral hematoma. The authors present our experiences with Ultrasound-guided catheter placement for lysis and drainage of ganglionic hematoma, with emphasis on technical aspects. Methods: The authors applied real-time ultrasonography for the aspiration of intracerebral hematoma in 6cases. Ultrasound-guided aspiration via a burrhole was performed under local anesthesia. We selected a temporal entry point instead of the frequently used precoronal approach in ganglionic hematoma. A burrhole was made 4 to 6cm posterior from posterior border of frontal process of the zygomatic bone at the level of 4 to 5cm above the external auditory meatus. Results: In all patients, the catheter was placed accurately into the hematoma target. All patients were irrigated with urokinase once to three times a day. The catheter could be removed within two or three days. The mean hematoma volume was reduced from initially 32mL to 5mL in an average of two days. There were no intraoperative complications related to the use of real-time ultrasonography and no postoperative infections were noted. Conclusion: Ultrasound allows an easy and precise localization of the hematoma and the distance from the surface to the target can be calculated. Ultrasound-guided catheter placement for fibrinolysis and hematoma drainage is a simple and safe procedure.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.323-326
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• 2007

Mobility Anchor Points are used for the mobility management in HMIPv6 networks. Currently a mobile node selects the MAP farthest away from itself as a new MAP among available candidates when it undertakes a macro handoff. With this technique, however, the traffic tends to be concentrated at a MAP with the largest domain size and the communication cost increases due to the distance between the mobile node and the MAP. In this work, we proposed a cost effective MAP selection scheme. When leaving the current MAP domain. the mobile node calculates the optimum MAP domain size to minimize the local mobility cost at the new MAP domain considering mobile node's velocity and packet transmission rate. The mobile node then selects a MAP domain of size close to the optimum domain size calculated among the candidate MAP domains. In this way, it is possible for the mobile node to select an optimal MAP adaptively taking the network and node states into account, thus reducing the communication cost.

• Journal of the Korean Society of Safety
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• v.14 no.4
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• pp.114-119
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• 1999

When NaOCl was generated and put into sea-water cooling machine in order to overcome the biological hindrances against sea-water cooling machine, it was converted into metallic ion, particularly Ca and Mg, as a hydrate in sea-water and is to stick to electrolyte as a side reaction. This phenomena make the distance between the electrolytes narrow to decrease the flow rate, which induces the local vortex flow which erodes the pole plate. Moreover, this increases the resistance of the electrolyte as well as voltage to decrease the electrolytic efficiency, which has curtailed a chlorine yield and caused a pole plate cut. We are able to overcome these problems by chemical cleaning and intend to extend the life-time of electrolyte and to increase output of the sea-water electrolysis facilities by studying optimal policy regarding chemical cleaning of electrolytic cell. Cleaning time of electrolytic facilities is determined when both increase in electrolytic efficiency and decrease in pole-plate voltage are 10%. At this time as operating current of electrolytic facilities is high, operating time is diminished. Whereas, parameter of end point determination according to cleaning is Mg ionic concentration in solution. When we use Cleaner as a 7wt% HCl, cleaning time is about 80min proper. We are able to maintain pole plate performance by protecting against pole plate cut by means of electrolytic by-product, improve operating rate of facilities, and cut down on maintenance expenditure after acidic cleaning.