• Journal of the Korean association of regional geographers
• /
• v.17 no.4
• /
• pp.432-442
• /
• 2011

Climatic variables such as temperature and precipitation tend to vary both in space and in time simultaneously. Thus, it is necessary to include space-time autocorrelation into conventional spatial interpolation methods for reliable time-series mapping. This paper introduces and applies space-time variogram modeling and space-time kriging to generate time-series temperature maps using hourly Automatic Weather System(AWS) temperature observation data for a one-month period. First, temperature observation data are decomposed into deterministic trend and stochastic residual components. For trend component modeling, elevation data which have reasonable correlation with temperature are used as secondary information to generate trend component with topographic effects. Then, space-time variograms of residual components are estimated and modelled by using a product-sum space-time variogram model to account for not only autocorrelation both in space and in time, but also their interactions. From a case study, space-time kriging outperforms both conventional space only ordinary kriging and regression-kriging, which indicates the importance of using space-time autocorrelation information as well as elevation data. It is expected that space-time kriging would be a useful tool when a space-poor but time-rich dataset is analyzed.

• Journal of Korean Library and Information Science Society
• /
• v.23
• /
• pp.363-404
• /
• 1995

This study is to set up a model of minimum and optimum standards for college and university library building areas in Korea. The results of this study are summarized as follows: 1. minimum standards(proposal) At first, Areas needed by factors of space component are as follows: User space --- 0.45 $m^{2}$ per student. Collection space --- 0.0107 $m^{2}$ per volume Staff space --- 10.1 $m^{2}$ per person Space attached to user, collection and staff space --- 5% of the sum of user, collection and staff areas(0.041 $m^{2}$ per student). Nonassignable space --- 25% of the sum of user, collection and staff areas (0.21 $m^{2}$ per student). Next, the formula to calculate the total area of the college and university library building is as follows: N = 0.45T $m^{2}$(a) + 0.0107V $m^{2}$(b) + 10.1S $m^{2}$(c) + 0.05(a+b+c) $m^{2}$, NS = 0.25N $m^{2}$. 2. Optimum standards(proposal) At first, Areas needed by factors of space component are as follows: User spae --- 0.64 $m^{2}$) per student. Collection space --- 0.01 $m^{2}$ per volume Staff space --- 9.7 $m^{2}$ per person Space attached to user, collection and staff space --- 5% of the sum of user, collection and staff areas(0.073 $m^{2}$ per student). Nonassignable space --- 25% of the sum of user, collection and staff areas(0.38 $m^{2}$ per student). Next, the formula to calculate the total area of the college and university library building is as follows: N = 0.64T $m^{2}$(a) + 0.01V $m^{2}$(b) + 9.7S $m^{2}$(c) + 0.05(a+b+c) $m^{2}$, NS = 0.25N $m^{2}$.

• Journal of Astronomy and Space Sciences
• /
• v.32 no.4
• /
• pp.305-310
• /
• 2015

In this study, we examined a morningside Pi2 pulsation, with a non-substorm signature, that occurred in very quiet geomagnetic conditions (Kp = 0) at 05:38 UT on December 8, 2012, using data obtained by Van Allen Probes A and B (VAP-A and VAP-B, respectively) and at a ground station. Using 1 sec resolution vector magnetic field data, we measured the X-component of the pulsation from the Abu Simbel ground station (L = 1.07, LT = UT +2 hr, where LT represents local time) in Egypt. At the time of the Pi2 event, Abu Simbel and VAP-A (L = 3.3) were in the morning sector (07:38 LT and 07:59 MLT, respectively, where MLT represents magnetic local time), and VAP-B was in the postmidnight sector (04:18 MLT and L = 5.7). VAP-A and VAP-B observed oscillations in the compressional magnetic field component (Bz), which were in close agreement with the X-component measurements of the Pi2 pulsation that were made at Abu Simbel. The oscillations observed by the satellites and on the ground were in phase. Thus, we concluded that the observed morningside Pi2 pulsation was caused by the cavity resonance mode rather than by ionospheric current systems.

• Journal of Broadcast Engineering
• /
• v.15 no.6
• /
• pp.749-756
• /
• 2010

The signal space diversity is one of the promising transmission techniques in next generation mobile TV service. However, DVB-T2 does not consider the multiple antennas (MIMO) so that the cyclic Q-delay method, a component interleaver in DVB-T2, causes a critical issue in detecting symbols at the receiver side by increasing the inter-symbol dependency. To solve this problem, the component-swapping technique is proposed, which limits the inter-symbol dependency in order to reduce detection complexity. In this paper, the achievable gain of a component-swapping technique combined with 16K LDPC code defined in DVB-T2 is evaluated by computer simulations. From the results, the gain is confirmed in terms of BER and receive complexity compared to legacy component interleaver methods.

• Journal of Information Technology Applications and Management
• /
• v.12 no.1
• /
• pp.111-123
• /
• 2005

Many indexing methods were proposed so that process moving object efficiently. Among them, indexing methods like the 3D R-tree treat temporal and spatial domain as the same. Actually, however. both domain had better process separately because of difference in character and unit. Especially in this paper we deal with limited region such as indoor environment since spatial domain is limited but temporal domain is grown. In this paper we present a novel indexing structure, namely STS-tree(Separation of Time and Space tree). based on limited region. STS-tree is a hybrid tree structure which consists of R-tree and one-dimensional TB-tree. The R-tree component indexes static object and spatial information such as topography of the space. The TB-tree component indexes moving object and temporal information.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.54 no.4
• /
• pp.171-178
• /
• 2005

The proposed dual-output DC-DC converter that bases on flyback converter can obtain two output voltage with non-isolated main-output and isolated sub-output at the same time using single-winding high frequency transformer. It can solve problems in multi-winding converter that use one main-switch, and also control quality of isolated sub-output voltage can be improved by additional sub-switch to the second. For analysis and design of the proposed converter system, converters are classified as operation mode from switching state and are become modeling by applying state space averaging method. Steady-state characteristics and dynamic characteristics are analyzed by DC component and perturbation component from state space averaging model. From experiment converter, validity of analysis and design for the propose converter system is confirm.

• Communications for Statistical Applications and Methods
• /
• v.10 no.1
• /
• pp.19-30
• /
• 2003

Spatiotemporal statistical models are used for analyzing space-time data in many fields, such as environmental sciences, meteorology, geology, epidemiology, forestry, hydrology, fishery, and so on. It is well known that classical spatiotemporal process modeling requires the estimation of space-time variogram or covariance functions. In practice, the estimation of such variogram or covariance functions are computationally difficult and highly sensitive to data structures. We investigate a Bayesian hierarchical model which allows the specification of a more realistic series of conditional distributions instead of computationally difficult and less realistic joint covariance functions. The spatiotemporal model investigated in this study allows both spatial component and autoregressive temporal component. These two features overcome the inability of pure time series models to adequately predict changes in trends in individual sites.

• Korean Institute of Interior Design Journal
• /
• v.21 no.1
• /
• pp.148-158
• /
• 2012

The objective of this study is to find a possible application of small space utilization of GangSo Housing, so called compact-but-effective housing, through analyzing that of Japanese small housing. We analyze openness of view and flexibility of spaces divided by the physical and architectural aspects as first component and the psychological and interior space aspects as second component. The results showed that Japanese small houses have various unit plan compared to uniformity of Korean houses. Openness of view in Japanese small housing is accomplished by letting in light from the outside using position and shape of the window, looking more spacious using courtyard, void spaces, or sliding door hanging from the ceiling, and creating deception of view using floor-wall plan and appropriate materials. Flexibility of spaces is achieved by combination of first and second components, multipurpose of space and furniture, and variety of storage methods. It is necessary to improve spatial efficiency with consideration of volume-metric planing rather than flat-plane and develop various unit plans to meet residents' needs and demands on compact-but-effective houses.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.2
• /
• pp.911-917
• /
• 2017

There are generally three folds when developing neural network classifiers. They are as follows: 1) discriminant function; 2) lots of parameters in the design of classifier; and 3) high dimensional training data. Along with this viewpoint, we propose space search optimized polynomial neural network classifier (PNNC) with the aid of data preprocessing technique and simultaneous tuning strategy, which is a balance optimization strategy used in the design of PNNC when running space search optimization. Unlike the conventional probabilistic neural network classifier, the proposed neural network classifier adopts two type of polynomials for developing discriminant functions. The overall optimization of PNNC is realized with the aid of so-called structure optimization and parameter optimization with the use of simultaneous tuning strategy. Space search optimization algorithm is considered as a optimize vehicle to help the implement both structure and parameter optimization in the construction of PNNC. Furthermore, principal component analysis and linear discriminate analysis are selected as the data preprocessing techniques for PNNC. Experimental results show that the proposed neural network classifier obtains better performance in comparison with some other well-known classifiers in terms of accuracy classification rate.

• Journal of Astronomy and Space Sciences
• /
• v.32 no.4
• /
• pp.317-325
• /
• 2015

Energy spectra of electron microbursts from 170 keV to 340 keV have been measured by the solid-state detectors aboard the low-altitude (680 km) polar-orbiting Korean STSAT-1 (Science and Technology SATellite). These measurements have revealed two important characteristics unique to the microbursts: (1) They are produced by a fast-loss cone-filling process in which the interaction time for pitch-angle scattering is less than 50 ms and (2) The e-folding energy of the perpendicular component is larger than that of the parallel component, and the loss cone is not completely filled by electrons. To understand how wave-particle interactions could generate microbursts, we performed a test particle simulation and investigated how the waves scattered electron pitch angles within the timescale required for microburst precipitation. The application of rising-frequency whistler-mode waves to electrons of different energies moving in a dipole magnetic field showed that chorus magnetic wave fields, rather than electric fields, were the main cause of microburst events, which implied that microbursts could be produced by a quasi-adiabatic process. In addition, the simulation results showed that high-energy electrons could resonate with chorus waves at high magnetic latitudes where the loss cone was larger, which might explain the decreased e-folding energy of precipitated microbursts compared to that of trapped electrons.