• The Journal of Engineering Geology
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• v.13 no.4
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• pp.419-428
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• 2003

In order to evaluate groundwater movement and the infiltration of contaminants, such as petroleum products, the determination of porosity and effective porosity is very important. Porosity and effective porosity are important physical parameters that determine the transfer and movement of water and solutes in porous media. Various methods of determining these parameters have been developed, with varying degrees of accuracy and applicability. Most of the existing methods produce static results. They do not produce instantaneous and real time of porosity and effective porosity in a porous media. In this study, we used a new permittivity method called Frequency Domain Reflectometry with Vector analyzer (FDR-V) to determine the porosity and effective porosity of some sand samples in the laboratory. The advantage of the FDR-V method is that it instantaneously determines the temporal variation of dielectric constants of porous media. Then, the porosity and the effective porosity of porous media are computed using well established empirical equations. Results obtained from the FDR-V method compared favorably with results from other permittivity methods such as gravimetric, injection and replacement tests. The ratio of effective porosity to porosity was 85 - 92 %, when FDR-V was used. This value compared favourably with 90 %, which has been usually quoted in previous studies. Considering the convenience and its applicability, the EDR-V permittivity holds a great potential in porous media and contaminant transport studies.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.2
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• pp.39-47
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• 2008

Among previous Side Channel Analysis (SCA) methods, Differential Power Analysis (DPA) based on the statistical characteristics of collected signals has been known as an efficient attack for uncovering secret key of cryptosystems. However, the attack performance of this method is affected very much by the temporal misalignment and noise of collected side channel signals. In this paper, we propose a new method to surmount the noise problem in DPA. The performance of the proposed method is then evaluated while analyzing the power consumption signals of Micro-controller chips during a DES operation. Its performance is then compared to that of the original DPA in the time and frequency domains. When we compare the experimental results with respect to the needed number of traces to uncover the secret key, our proposed method shows the performance enhancement 33% in the time domain and 50% in the frequency domain.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.3
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• pp.165-176
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• 2018

To solve the inconsistencies between realistic boundaries and the cadastral record boundaries, the cadastral resurvey project has been funded by a large budget since 2012 and executed over a long period of time until 2030. However, if the causes of inconsistencies are not analyzed and addressed, these inconsistencies could possibly reoccur. Even though the causes of inconsistencies can be defined in several aspects, including regulations, surveying methods, and management of cadastre maps or survey results, and so on, this study focuses on analyzing the inconsistency problems in the management of cadastre maps or survey results. In order to resolve the problems in inconsistencies between the cadastre maps and survey results, the study proposes to develop the cadastre data model based on LADM (Land Administration Domain Model) to manage the cadastre maps and survey results in better ways. In order to proposed the Cadastre Data Model, we analyzed the cadastre management system implemented in Korea and identified requirements to resolve the problems in inconsistencies, which are considered in the proposed data model as follows: 1) cadastral management system based on individual parcels, 2) synthesis of a realistic boundary and cadastral record boundary, 3) management of official and sharing reference data, 4) consistent management of survey results and parcel boundaries, 5) temporal managements of parcel boundaries. In the end, this study proposes a cadastral data model based on the LADM to integrate and manage the cadastral surveying results of the new cadastral management system.

• Journal of Korea Spatial Information System Society
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• v.7 no.1 s.13
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• pp.77-89
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• 2005

Recently, application area on the Location Based System(LBS) is increasing because of development of mobile-communication and GPS technique. Previous studies on the index of moving objects are classified as either index for past trajectories or current/future positions. It is necessary to develop a unified index because many applications need to process queries about both past trajectories and current/future positions at the same time. In this paper, the past trajectories of moving objects are represented as line segments and the current and future positions are represented as the function of time. We propose a new index called PCR-tree(Past, Current R-tree) for unification of past, current and future positions. Nodes of the index have bounding boxes that enclose all position data and entries in the nodes are accessed with only one interface. We implement the proposed index and show a feasibility of processing the queries about temporal-spatial domain with the query tool which we develop.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.2
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• pp.307-318
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• 2013

Smart grid is composed of variable domains including different systems, and different types of the access control are needed in the multiple domain. Therefore, the access control model suitable for the smart grid environment is required to minimize access control error and deny the unauthorized access. This paper introduce the access control requirements in the smart grid environment and propose the access control model, SG-RBAC, satisfied with the requirements. SG-RBAC model imposes constraints on the access right activation according to the user property, the role property, and the system property. It also imposes constraints on the delegation and the inheritance of access right according to temporal/spatial information and a crisis occurrence.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.1
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• pp.46-50
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• 2015

The previous studies showed that the visual imagery activated the occipital and posterior inferior temporal area of the brain, and the damage to the occipital cortex impaired the visual mental imagery. We studied current-source distribution of electroencephalography (EEG) to observe neuronal activity during imagery tennis playing. Eleven healthy volunteers were enrolled. All volunteers were right-handed males and novices for tennis playing. The mean age of them was 24.9 years. The EEGs were recorded on the scalp electrodes located according to the International 10~20 System. The number of electrodes was 25 channels including subtemporal electrodes. The EEG recording session was 13 min including 5 segments: resting-I, scenery-slide show, resting-II, watching tennis-game video, and imagery-tennis playing. The recoding durations were 3, 2, 3, 2, and 3 min respectively. Five 'artifact free 3-sec segments' were selected in each segment of 'imagery-tennis playing' and 'resting-II'. We did the frequency domain analysis with the EEG segments using a distributed model of current-source analysis. The statistical-nonparametric maps (SnPMs) were obtained between the segments of 'imagery-tennis playing' and the segments of 'resting-II' (p<0.01). The significant change of current-source density was observed only in alpha-2 frequency band (10~12 Hz). The current-sourcedensity was increased in the hippocampus, parahippocampus, and occipital fusiform gyrus in the right cerebral hemisphere (p<0.01). Imaginary-tennis playing may activate the hippocampal-occipital alpha networks of nondominant hemisphere.

• Journal of Biomedical Engineering Research
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• v.28 no.5
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• pp.636-646
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• 2007

Adequate postural control depends on the spatial and temporal integration of vestibular, visual, and somatosensory information. Especially, the musculoskeletal function is essential to maintain the postural control. The experimental studies was performed on the muscular activities in the lower extremities during maintaining and moving exercises on an unstable platform with Magneto Rheological(MR) dampers. The unstable platform of the developed system was controlled by electric currents to the MR dampers. A subject executed the maintaining and moving exercises which are presented through the display monitor. The electromyographies of the eight muscles in lower extremities were recorded and analyzed in the time and the frequency domain: the muscles of interest were rectus femoris(RF), biceps femoris(BF), tensor fasciae latae(TFL), vastus lateralis(VL), vastus medialis(VM), gastrocnemius(Ga), tibialis anterior(TA), Soleus(So). The experimental results showed that the muscular activities differed in the four moving exercises and the nine maintaining exercises. For the anterior-posterior pattern, the TA showed highest activities; for the left-right pattern, the TFL; for the 45, $-45^{\circ}$ pattern, the TFL and TA. Also, the rate of the increase in the muscular activities were affected by the condition of the unstable platform with MR dampers for the maintaining and moving exercises. The experimental results suggest that the choice of different maintaining and moving exercises could selectively train different muscles in various intensity. Futhermore, the findings suggested that the training using this system can improve the ability of postural control.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.1
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• pp.15-25
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• 2009

Donghae city is one of the most representative cement industrial city in Korea. The area is faced with the East Sea to the East and with high montane region of Tae-Back mountain range to the West. Many pollutant sources of air pollution are located near the coast, but the largest point sources of the region are located at the bottom of the mountain area in Donghae city. The local wind is highly affected by local topography and plays an important role in transport and dispersion of contaminants from the pollution sources. This study was designed to evaluate enhancement of MM5 predictions by using Four Dimensional Data Assimilation (FDDA), the SONDE data and the national meteorological station, data only. The alternative meteorological fields predicted with and without FDDA were used to simulate spatial and temporal variations of NOx in combined with Atmospheric Dispersion Models (CALPUFF). For the modeling domain, the alternative meteorological fields with 1.1 km spatial resolution were interpolated to the CALMET with 0.5 km resolution. The vertical layers set to have 35 and 12 layers for MM5 and CALPUFF, respectively. MM5 with the FDDA did not resulted in significant improvement of meteorological field prediction in Donghae region, which is primarily because of complex geography and wind scheme. The result of CALPUFF, however, showed reduction of uncertainty errors by using the interpolation scheme of the actual measurement data.

• Journal of Environmental Science International
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• v.22 no.9
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• pp.1115-1129
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• 2013

The study area is located on the western coast, and the inner development construction has been ongoing since 2011. The purposes of current study are to effectively simulate and quantitatively predict a temporal and spatial distributions of water temperature and salinity due to the stages of inner development construction in saemangeum reclaimed area. The transient-state numerical modeling using EFDC model is done, and the numerical simulation results are validated reasonably by repetitive numerical model calibration procedures with respect to field measurements of water temperature and salinity. The spatial distributions of water temperature and salinity show similar trends before and after construction of the dikes. In spring season, the salinity has maximum value of 21 psu, while, in summer season, the salinity shows 7 psu in a whole modeling domain. Thus, it is clearly observed that salt water is replaced by freshwater. However, the salinity and temperature reach their initial conditions at the end of the year. The salinity after construction of the dikes is lower than that before construction of them at Mankyeong area. On the other hands, after construction of the dikes, the salinity after dredging operations is higher than that before dredging. Because drastical increasing of water volume in Saemangeum Lake leads to increasing of stagnation time at bottom layer, and salt water is easily intruded to the two estuaries. Therefore, it may be concluded that hydrodynamic characteristics on Saemangeum are dominated by either Mankyeong and Dongjin discharge or sluice gates in/out-flow amounts, and thus they must be properly considered when rigorous and reasonable predictions of water temperature and salinity according to the stages of inner development construction.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.8
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• pp.1675-1685
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• 2012

DVC (Distributed Video Coding) technique plays an essential role in providing low-complexity video encoder. But, in order to achieve the better rate-distortion performances, most DVC systems need feedback channel for parity bit control. This causes the DVC-based system to have high decoding latency and becomes as one of the most critical problems to overcome for a real implementation. In order to overcome this problem and to accelerate the commercialization of the DVC applications, this paper analyzes an effect of LDPCA frame size for adaptive LDPCA frame-based parity bit request estimations. First, this paper presents the LDPCA segmentation method in pixel-domain and explains the temporal-based bit request estimation method and the spatial-based bit request estimation method using the statistical characteristics between adjacent LDPCA frames. Through computer simulations, it is shown that the better performance and fast decoding is observed specially when the LDPCA frame size is 3168 in QCIF resolution.