• Journal of The Korean Digital Architecture Interior Association
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• v.11 no.1
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• pp.33-42
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• 2011

As the development of construction technology and new materials, building requirements has been varied gadually. Comfortable environment and serviceability of production activity and energy conservation are being dealt with very seriously. Recently localization of engineering technology of Power Plant, however, construction materials and domestic technology are being developed forcingly. According to above topics this thes is going to study roof waterproofing, thermal insulation and evaluate adiabatic performance and evaluation of properties of waterproofing materials and energy conservation. The results of studying and evaluating of roof waterproofing, thermal insulation and adiabatic performance of Power Plant are as follows. 1. Sheet waterproofing method is better than that of asphalt waterproofing method in that adaptability of wearhertight, thermal resistant, contraction and expansion. 2. It is required to replace polyurethane or ethylene used as thermal insulation with rock wool which is noncombustible materials. 3. It is recommended to usd outer insulation method than inner insulation method due to superioty of outer insulation method. Efficiency of insulation materials used in power plant is generally good except perlite mortar used in the power plant(YGN 1-2, GRI 1-2).

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.217-219
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• 2007

With the wide spread of direct current(DC) electric railroads in Korea, the stray current or leakage currents from negative return rails become a pending problem to the safety of nearby underground Infrastructures. The most widely used mitigation method for this interference is the stray current drainage method, which connects the underground metallic structures to the rails with diodes (polarized drainage) or thyristor (forced drainage). This method, however, inherently possesses some drawbacks such as an increase of total leakage torrents from rails, expansion of interference zone, etc. In order to resolve these drawbacks, we developed a rapid potential-controled rectifier and applied to a depot area where stray current inference is very severe. The effect of this method was analyzed from the field tell data and we suggest this method can be an excellent alternative to the drainage-bond-based mitigation methods.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.3
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• pp.8-17
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• 2015

In this research, low fidelity air/heat load analysis was conducted for the intake of high speed vehicle. For air/heat load calculations, aerodynamic properties at the surface and the boundary layer edge were estimated using Taylor-Maccoll equation for conical flow, shockwave relation and Prandtl-Meyer expansion equation for internal and external flow. Couette flow assumption and Reynolds analogy were used in order to calculate convective heat transfer coefficient. In order to calculate skin friction coefficient for heat transfer coefficient analysis, Van Driest method II and Reference Enthalpy method were considered. An axis symmetric SCRAMJET model was selected as a reference configuration for verifying the proper implementation of the present method. Comparison of the results using the present method and Computational Fluid Dynamic analysis showed that the present method is valuable for efficiently providing pressure and heat loads for air-intake structure design of the high speed air vehicle.

• Journal of Korea Multimedia Society
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• v.7 no.4
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• pp.579-591
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• 2004

This paper presents a new arc segmentation method which extracts curves from simple drawing consisted of straight lines and curves and segments them into circular arcs. First, it finds center points and finds line segments and curve segments by tracing connected center points. Next, it expands the segment by searching neighbor segment at the two endpoints. Next, it removes straight lines and segments the extracted curves into circular arcs by using the recursive subdivision method. The proposed method has been compared with previous vectorization software and vector based arc segmentation method. Experimental results show that the proposed method produces more correct results for the curves which contain intersection with other lines or curves.

• The Journal of the Acoustical Society of Korea
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• v.18 no.4
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• pp.71-77
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• 1999

Exact forward modeling of acoustic propagation is crucial in MFP such as inverse problems and various other acoustic applications. As acoustic propagation in shallow water environments become important, range dependent modeling has to be considered of which PE method is considered as one of the most accurate and relatively fast. In this paper higher order numerical rode employing the PE method is developed. To approximate the depth directional operator, Galerkin's method is used with partial collocation to lessen necessary calculations. Linearization of tile depth directional operator is achieved via expansion into a multiplication form of (equation omitted) approximation. To approximate the range directional equation, Crank-Nicolson's method is used. Final1y, numerical self stater is employed. Numerical tests are performed for various occan environment scenarios. The results of these tests are compared to exact solutions, OASES and RAM results.

• Journal of Information Technology Services
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• v.19 no.3
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• pp.139-149
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• 2020

There are now many different commercial weather sensors suitable for smart farms, and various smart farm devices are being developed and distributed by companies participating in the government-led smart farm expansion project. However, most do not comply with standard specifications and are therefore limited to use in smart farms. This paper proposed the connecting structure of operating non-standard node devices in smart farms following standard specifications supporting smart greenhouse. This connecting structure was proposed as both a virtual node module method and a virtual node wrapper method. In addition, the SoftFarm2.0 system was experimentally operated to analyze the performance of the implementation of the two methods. SoftFarm2.0 system complies with the standard specifications and supports non-standard smart farm devices. According to the analysis results, both methods do not significantly affect performance in the operation of the smart farm. Therefore, it would be good to select and implement the method suitable for each non-standard smart farm device considering environmental constraints such as power, space, distance of communication between the gateway and the node of the smart farm, and software openness. This will greatly contribute to the spread of smart farms by maximizing deployment cost savings.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.5
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• pp.67-75
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• 1999

This paper presents a production method to GRM coefficients which are consist of $P^n$ polarities to n variables over GF(p). In general production method to GRM coefficients is derived from RM coefficients to polarity 0 using RM expansion and extended to GRM coefficients. The procedure of proposed production method to GRM coefficients is consists of 2 steps. First, obtain the optimal polarity which is contains a minimal operation to single variable and then apply the same process to all generation process of GRM coefficients using cyclic property of the polarity. Proposed method simplify the generation procedure and reduces a number of operators because of the cyclic property of polarity.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.577-584
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• 2000

Seismic refraction survey was peformed for 10 lines along NE-SW and NW-SE directions above Nampoong gallery at Makyo-ri, Dogye, Samcheok, Kangwon-do. 48 geophones were laid in line with the interval of 1m, and a 5Kg hammer was used as a source at 5 points for each line. Data processing was done using reciprocal time method, GRM, and traveltime tomography which utilizes wavefront expansion method for forward process and SIRT for inversion. The result shows that the first layer has its lower boundary between 3.49m and 8.88m. The P-wave velocity of the first and the second layer were estimated as 270 360m/s and 1550 1940m/s respectively. When the boundary of the first and second layer is smooth enough and the velocity difference is large enough, GRM has little advantage over reciprocal time method. The result of reciprocal method and traveltime tomography shows consistency. The northeast part of the boundary has syncline structure, which is similar to the topography above. This implies that the collapse of the cavities of Nampoong gallery result in the subsidence of the ground surface. The subsidence is in progress across the Youngdong railroad, therefore a proper reinforcement work is required.

• Journal of computational fluids engineering
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• v.9 no.4
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• pp.55-63
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• 2004

The three-dimensional Stokes flow within a staggered screw channel is obtained by using a finite volume method. The geometry is intended to mimic the single screw extruder having staggered arrangement of flights. The flow solution is then subjected to the analysis of the stirring performance. In the analysis of the stirring performance, the stretching-mapping method developed by the author is employed for calculating the materials' stretching exponents, which are to be used in quantification of the mixing effect. The numerical results Indicate that the staggered geometry gives indeed far much better stirring-performance than the standard (nonstaggered) flight geometry. It was also shown that care must be given to the selection of the basis planes for evaluating the local stretching rate, and it turns out that the best method (H-method) has its basis plane just on the half way between the past and future evolution of fluid particles subjected to the defromation. In evaluating the stretching exponent, the expansion ratio must be considered which is one of the characteristic differences of the actual three-dimensional flows from the two-dimensionmal counterparts. The larger axial pressure-difference causes in general the smaller stirring performance while the flow rate is increased. The smaller channel length also increases the stirring performance.

• Journal of computational fluids engineering
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• v.2 no.1
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• pp.66-72
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• 1997

Optimum nozzle design exploiting the method of characteristic(M.O.C) has been in application as an efficient design methodology targeting a less weighted and short expansion nozzle. This paper treats the optimum nozzle design and the analysis of the inviscid compressible flow inside. Based on traditional Rao's method, the optimum nozzle design is coded with minor modifications for the identification of the control surface across which the mass flux should be conserved. Internal flow field is simulated numerically by M.O.C and implicit/explicit Taylor-Galerkin finite element method(F.E.M) with the aid of adaptive remeshing to capture the shock wave, hence improve the accuracy. Designed and calculated flow fields due to the separate analyses show that the mass flux predicted by optimum nozzle design with M.O.C is not conserved across the control surface and the sonic line should be located upstream of the nozzle throat. Rao's optimum nozzle design methodology exaggerates the momentum thrust and tends to overemphasize the engine performance loss.