• The Journal of Society for e-Business Studies
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• v.12 no.3
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• pp.211-234
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• 2007

In e-business, XML is a major format of data and it is essential to efficiently process queries against XML data. XML query caching has received much attention for query performance improvement. In employing XML query caching, some efficient technique of cache replacement is required. The previous techniques considered as a replacement unit either the whole query result or the path in the query result. The former is simple to employ but it is not efficient whereas the latter is more efficient and yet the size difference among the potential victims is large, and thus, efficiency of caching would be limited. In this paper, we propose a new technique where the element in the query result is are placement unit to overcome the limitations of the previous techniques. The proposed technique could enhance the cache efficiency to a great extent because it would not pick a victim whose size is too large to store a new cached item, the variance in the size of victims would be small, and the unused space of the cache storage would be small. A technique of XML semantic cache replacement is presented which is based on the replacement function that takes into account cache hit ratio, last access time, fetch time, size of XML semantic region, size of element in XML semantic region, etc. We implemented a prototype XML semantic cache system that employs the proposed technique, and conducted a detailed set of experiments over a LAN environment. The experimental results showed that our proposed technique outperformed the previous ones.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1375-1381
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• 2011

Combustion processes in an optically-accessible single-cylinder heavy-duty diesel engine equipped with a highpressure common-rail injection system were investigated for JP-8 and diesel. Direct imaging and two-color thermometry were employed to verify the emission trend for both fuels. The combustion process was characterized by image analysis with focus on luminosity. The results of two-color thermometry were analyzed on the basis of the flame temperature and KL factor distribution. Analysis of the combustion process by direct imaging showed that the ignition delay was longer for JP-8 than for diesel, while the flame was extinguished rapidly. Analysis of the flame luminosity showed that the combustion intensity was higher for diesel and that the flame lasted for a longer duration in this case. Two-color thermometry results showed that the high-temperature region extended over a large area during JP-8 combustion, implying the formation of a large amount of $NO_x$. In addition, the KL factor showed low level over a large area and relatively homogeneous in the case of JP-8 combustion, which implied that less smoke was produced when using this fuel.

• The KIPS Transactions:PartA
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• v.17A no.6
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• pp.265-274
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• 2010

As the process technology scales down and integration densities continue to increase, interconnection has become one of the most important factors in performance of recent multi-core processors. Recently, to reduce the delay due to interconnection, 3D architecture has been adopted in designing multi-core processors. In 3D multi-core processors, multiple cores are stacked vertically and each core on different layers are connected by direct vertical TSVs(through-silicon vias). Compared to 2D multi-core architecture, 3D multi-core architecture reduces wire length significantly, leading to decreased interconnection delay and lower power consumption. Despite the benefits mentioned above, 3D design technique cannot be practical without proper solutions for hotspots due to high temperature. In this paper, we propose three floorplan schemes for reducing the peak temperature in 3D multi-core processors. According to our simulation results, the proposed floorplan schemes are expected to mitigate the thermal problems of 3D multi-core processors efficiently, resulting in improved reliability. Moreover, processor performance improves by reducing the performance degradation due to DTM techniques. Power consumption also can be reduced by decreased temperature and reduced execution time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.11
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• pp.1094-1103
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• 2012

Recently, software industry regarding national defense increases system development of distributed simulation system of M&S based to overcome limit of resource and expense. It is one of key technologies for offering of mutual validation among objects and reuse of objects which are discussed for developing these systems. RTI, implementation of HLA interface specification as software providing these technologies uses Federation Object Model for exchanging information with joined federates in the federation and each federate has a characteristic that is supposed to have identical FOM in the federation. This technology is a software which is to provide the core technology which was suggested by the United state's military M&S standard framework. Simulator, virtual simulation, and inter-connection between military weapons system S/W which executes on network which is M&S's core base technology, and it is a technology which also can be used for various inter-connection between S/W such as game and on-line phone. These days although RTI is used in military war game or tactical training unit field, there is none in Korea. Also, it is used in mobile-game, distribution game, net management, robot field, and other civilian field, but the number of examples are so small and informalized. Through this developing project, we developed the core technique and RTI software and provided performance of COTS level to improve communication algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.4C
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• pp.341-348
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• 2009

In this paper, we propose a grouping technique for the SDD(Synchronous Digital Duplexing) based on OFDMA(Orthogonal Frequency Division Multiple Access). The SDD has advantages of increasing data efficiency and flexibility of resource since SDD can transmit uplink signals and downlink signals simultaneously by using mutual time information and mutual channel information, obtained during mutual ranging process. However, the SDD has a disadvantage of requiring additional CS to maintain orthogonality of OFDMA symbols when the sum of mutual time difference and mutual channel length between AP(access point) and SS(subscriber station) or among SSs are larger than CP length. In order to minimize the length of CS for the case of requiring additional CS in SDD, we proposes a grouping technique which controls transmit timing and receive timing of AP and SS in a cell by classifying them into groups. Performances of the proposed grouping technique are evaluated by computer simulation.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.6
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• pp.532-542
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• 2009

Dynamic Thermal Management (DTM) technique is generally used for reducing the peak temperature (hotspot) in the microprocessors. Despite the advantages of lower cooling cost and improved stability, the DTM technique inevitably suffers from performance loss. This paper proposes the DualFloating-Point Adders Architecture to minimize the performance loss due to thermal problem when the floating-point applications are executed. During running floating-point applications, only one of two floating-point adders is used selectively in the proposed architecture, leading to reduced peak temperature in the processor. We also propose a new floorplan technique, which creates Space for Heat Transfer Delay in the processor for solving the thermal problem due to heat transfer between adjacent hot units. As a result, the peak temperature drops by $5.3^{\circ}C$ on the average (maximum $10.8^{\circ}C$ for the processor where the DTM is adopted, consequently giving a solution to the thermal problem. Moreover, the processor performance is improved by 41% on the average by reducing the stall time due to the DTM.

• Atmosphere
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• v.16 no.3
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• pp.247-257
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• 2006

The Yeong-dong heavy snowfall forecast supporting system has been developed during the last several years. In order to construct the conceptual model, we have examined the characteristics of heavy snowfalls in the Yeong-dong region classified into three precipitation patterns. This system is divided into two parts: forecast and observation. The main purpose of the forecast part is to produce value-added data and to display the geography based features reprocessing the numerical model results associated with a heavy snowfall. The forecast part consists of four submenus: synoptic fields, regional fields, precipitation and snowfall, and verification. Each offers guidance tips and data related with the prediction of heavy snowfalls, which helps weather forecasters understand better their meteorological conditions. The observation portion shows data of wind profiler and snow monitoring for application to nowcasting. The heavy snowfall forecast supporting system was applied and tested to the heavy snowfall event on 28 February 2006. In the beginning stage, this event showed the characteristics of warm precipitation pattern in the wind and surface pressure fields. However, we expected later on the weak warm precipitation pattern because the center of low pressure passing through the Straits of Korea was becoming weak. It was appeared that Gangwon Short Range Prediction System simulated a small amount of precipitation in the Yeong-dong region and this result generally agrees with the observations.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.9
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• pp.1477-1484
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• 2005

The effects of various seasoning components, pH of seasoning solution, heating time and storage temperature were investigated on the color and textural properties of the salted radish root (nanmooji) The effects of individual seasoning components in the salted radish root, additives of polyphosphate (AD3), citric acid (AD5), malic acid (AD2) delayed the color changes and softening more, compared to control soaked in water. On the other hand, additives of potassium sorbate (AD1), succinic acid (AD7), MSG (AD8), saccharin (AD6) accelerated the color changes and softening of the salted radish roots. The effects of pH of seasoning solution($X_1$), and heating time ($X_2$) were central composite design and response surface analysis. R- square represented dependent variables correlated independent variables ($X_1,\;X_2$), showed over 0.8 in the color and area value calculated thickness and firmness of salted radish root. Especially, R- square of 'b' represented 'yellow-green' was 0.899. And the result of crossing analysis of individual independent variables ($X_1,\;X_2$), showed that both independent variables had significant effects on the color and textural changes of the salted radish root. The salted radish root increased its color changes and softening, rapidly at $40^{\circ}C$, compared to the other storage temperatures at most storage periods.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5947-5955
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• 2013

This study was intended to estimate the axial deformation of joint between pavement modules in the rapid-constructible modular pavement system, and to investigate the applicability of two-phase composites for a joint material, which was composed of cement paste, epoxy, or polyurethane as a matrix and sand as particles. A case which had supports under the pavement module as well as a case which the module was put on roadbed directly were considered in FEM analysis for the axial deformation. The effect of self-weight, live load, thermal change, and drying shrinkage were estimated and the thermal change was found to cause the largest deformation compared to the others. Deformation capacity of two-phase composites was predicted using the modified shear-lag model. In the analytical results for the elastic modulus and maximum tensile strain with different volume fractions of sand, 20~30 % replacement of sand was revealed to satisfy the required strain capacity with economy when if the width of joint was designed to be 15~20 mm.

• Korean Journal of Remote Sensing
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• v.31 no.2
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• pp.101-110
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• 2015

Synthetic Aperture Radar Interferometry (InSAR) is affected by various noise source such as atmospheric artifact, orbital error, processing noise etc.. Especially, one of the dominant noise source for long-wave SAR system, such as ALOS PALSAR (L-band SAR satellite) is the ionosphere effect because phase delays on radar pulse through the ionosphere are proportional to the radar wavelength. To avoid misinterpret of phase signal in the interferogram, it is necessary to detect and correct ionospheric errors. Recently, a MAI (Multipler Aperture SAR Interferometry) based ionospheric correction method has been proposed and considered one of the effective method to reduce phase errors by ionospheric effect. In this paper, we introduce the MAI-based method for ionospheric correction. Moreover we propose an efficient method that apply the method over non-coherent area using directional filter. Finally, we apply the proposed method to the ALOS PALSAR pairs, which include the west sea coast region in Korea. A polynomial fitting method, which is frequently adopted in InSAR processing, has been applied for the mitigation of phase distortion by the orbital error. However, the interferogram still has low frequency of Sin pattern along the azimuth direction. In contrast, after we applied the proposed method for ionospheric correction, the low frequency pattern is mitigated and the profile results has stable phase variation values within ${\pm}1rad$. Our results show that this method provides a promising way to correct orbital and ionospheric artifact and would be important technique to improve the accuracy and the availability for L-band or P-band systems.