• Journal of computational fluids engineering
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• v.20 no.3
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• pp.8-14
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• 2015

More and more, spaces are decreasing which satisfy multiple requirements for wind power plants. However, areas which have excellent wind resources and are free to civil complaints occupy a large space, although they are exposed to the cryogenic environment. This study conducted a thermal-fluid analysis of a cryogenic chamber for testing large wind turbine parts exposed to the cryogenic environment. The position of supply air is placed to the upper area to compare each cooling performance for each location of various outlets in mixing ventilated conditions. The study carried out CFD analysis for the chamber both with and without a test object. For the cases without the test object, the air temperature of the upper supply and down extract type chamber was cooled faster by 5-100% than the others. However, for the cases with the test object, the object temperature of upper supply and center extract on the opposite side type chamber was cooled faster by 33-132% than the others. The cooling performance by the air inside the chamber and the test object did not show the same pattern, which implicates the need to consider the cooling performance by not only the air but also the test object in the large cryogenic chamber design for testing large parts.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.2
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• pp.81-88
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• 2016

There are many types of national and international standards for low temperature tests depending on the products. This study conducted CFD analysis and estimation of the energy efficiency of the chamber both with and without a test object by considering variations of COP and specific volume according to temperature. The supply air was located in the upper area to compare the cooling performance for each location using various outlets in mixed ventilated conditions. For cases without the test object, the air temperature of the upper supply and center extract on the opposite side type chamber cooled faster than other areas by 4.3~29.8%. However, for cases with the test object, the object temperature of the upper supply and lower extract type chamber cooled faster than the other areas by 7.2~31.5%. The cooling efficiency of the air inside the chamber and the test object did not show the same pattern, which indicates the need to consider the cooling performance by not only the air but also the test object in the cryogenic chamber design for testing.

• Journal of the Institute of Convergence Signal Processing
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• v.4 no.4
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• pp.40-46
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• 2003

In this research, we accomplished the interpreting about the vibration of the object, which is the out of plane displacement in the Electronic Speckle Pattern Interferometry(ESPI), one of the optical measuring technique. The vibrating object has a inherent nodal line, therefore we can get the information about the vibration of the object by interpreting it. we used a speaker and a cantilever plate for a measurement object, and interpreted it qualitatively by using the Time-Average ESPI. In this experimental result, the speaker has the lower mode of fringe at 550Hz, 570mV, and the higher mode of fringe at 950Hz, 570mV This ESPI is a non-destructive test, and because of using the laser at measuring, it has a high resolution. The ESPI can test vibration mode regardless of the test object size, because the area which illuminated laser is the test area.

• Journal of the Korea Computer Graphics Society
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• v.6 no.1
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• pp.11-17
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• 2000

We present collision-handling method that includes self-penetration in the case of the colliding between rigid and deformable objects. The collision between objects is detected through the overlap test to the hierarchical structures of the objects. For detecting the collision between the objects at in-between frame, we try overlap test using the structures of a dummy and the rigid objects in addition to the test between the rigid and deformable objects. The dummy object is made from the rigid objects moving direction. When collision occurs, a deformable object must be deformed, as the object doesn't permit penetration. Self-penetration may occur during the object is deformed. It is rapidly detected between the object and a dummy object of another type. The dummy object is made from the object's deformation area between two continuous frames. We constrain the object is deformed until it is self-contacted. Our method can be applied without concerning of the shape of a object.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.5
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• pp.734-738
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• 2010

Object Generator is a software to provide simulation object data(aircraft, ship, submarine, missile, torpedo) for sumulators in LBTS(Land Based Test System). but there is a burden to the system, because Object generator needs to send many object's data, display objects in a tactical screen, show object's information in a list in 1 second. This paper suggests a parallel software structure taking a few factors(deadlock, dependency) into consideration. At last, the paper shows the performance of the parallel structure's software compared with the former structure's software.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.2
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• pp.63-70
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• 1997

This paper proposes a new algorithm for recognizing polyhedral objects using a single 2-D image. It is base don a new representation scheme having two level hierarchey. In the lower level, geometrical features of each primitive surface are represented using their signatures and the variation of signature due to rotation is represented suing the rotation map. In the higher level, topological features are represented in the inter-surface description table(SDT). Based on the proposed representaton scheme, loer level database searched to find a matching primitive surface. The srotation map determines the degree of rotation as well as the matchness. If all surfaces in a test object find their matching primitive surfaces, its structural information is compared with the SDTs of object models. If primitive surfaces of a test object equal to tha tof certain model and satisfy inter-surfaces relationship in SDT, a test object is recognized as the model.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.4
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• pp.424-430
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• 2008

A new active vibration measurement system in electric power transmission line is presented, using in the nondestructive test. With a permanent magnet and a couple of coils, the system exerts impact force to a test object and in turn picks up the vibration of the object. The natural frequency with the amplitude obtained from the system are used as a basis for the detection of defects in the object. The system is controlled by an electronic device designed to facilitate the fully automated testing process with consistent repeatability and reliability which are essential to the nondestructive test. The system is expected to be applied to the wide area of defect detection including the classification of mechanical parts in production and inspection processes.

• The KIPS Transactions:PartD
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• v.8D no.6
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• pp.843-852
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• 2001

Statistics concerning software errors indicate that more errors are introduced in analysis and design phase than implementation phase. Therefore, it is needed to check whether the design modeling is appropriate for own function and structure. This paper discussed the effective test method for the object-oriented design model, i.e., UML. A new method was proposed for generating test data. This method consists of category partition theory by the representation each element in UML model with OCL (Object Constraint Language). Test data generated in this way can be used for testing the source code functionality as well as for checking the design model.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.37 no.6
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• pp.1-8
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• 2000

This paper describes an algorithm for semantic video object tracking using semi automatic method. In the semi automatic method, a user specifies an object of interest at the first frame and then the specified object is to be tracked in the remaining frames. The proposed algorithm consists of three steps: object boundary projection, uncertain area extraction, and boundary refinement. The object boundary is projected from the previous frame to the current frame using the motion estimation. And uncertain areas are extracted via two modules: Me error-test and color similarity test. Then, from extracted uncertain areas, the exact object boundary is obtained by boundary refinement. The simulation results show that the proposed video object extraction method provides efficient tracking results for various video sequences compared to the previous methods.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.287-290
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• 2004

In the moving object database system, spatiotemporal join is very import operation when we process join moving objects. Processing time of spatio-temporal join operation increases by geometric progression with numbers of moving objects. Therefore efficient methods of spatio-temporal join is essential to moving object database system. In this paper, we propose spatio-temporal join algorithm with TB-Tree that preserves trajectories of moving objects, and show result of test. We first present basic algorithm, and propose cpu-time tunning algorithm and IO-time tunning algorithm. We show result of test with data set created by moving object generator tool.