• Journal of KIISE:Databases
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• v.36 no.1
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• pp.50-62
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• 2009

In wireless and mobile environments, data broadcasting is recognized as an effective way for data dissemination due to its benefits to bandwidth efficiency, energy-efficiency, and scalability. In this paper, we address the problem of delayed query processing raised by tree-based index structures in wireless broadcast environments, which increases the access time of the mobile clients. We propose a novel distributed index structure and a clustering strategy for streaming XML data which enable energy and latency-efficient broadcast of XML data. We first define the DIX node structure to implement a fully distributed index structure which contains tag name, attributes, and text content of an element as well as its corresponding indices. By exploiting the index information in the DIX node stream, a mobile client can access the wireless stream in a shorter latency. We also suggest a method of clustering DIX nodes in the stream, which can further enhance the performance of query processing over the stream in the mobile clients. Through extensive performance experiments, we demonstrate that our approach is effective for wireless broadcasting of XML data and outperforms the previous methods.

• The Journal of Korean Obstetrics and Gynecology
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• v.28 no.4
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• pp.21-30
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• 2015

Objectives : The purpose of this study was to analyze the characteristics of the pulse energy in women who complained mild hyperemesis gravidarum. Methods : We analyzed the values of pulse energy on 14 patients who suffered mild hyperemesis gravidarum. The patients’ symptoms were assessed by PUQE (Pregnancy-Unique Quantification of Emesis scale). Statistical analysis was performed using SPSS 18.0 for window program, one way ANOVA, pearson correlation coefficient. Results : The results were as follows. 1. There were no statistically significant pulse energy differences. 2. The Chon pulse energy showed negative correlations with each Kwan and Cheok. 3. PUQE score showed positive correlations with right Chon pulse energy and negative correlations with right Kwan pulse energy. Conclusions : The result suggested that PUQE score changes be positive related with spleen pulse energy and negative related with lung pulse energy.

• Steel and Composite Structures
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• v.22 no.3
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• pp.589-611
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• 2016

The primary objectives of this research are to investigate the energy factor response of steel moment resisting frame (MRF) systems equipped with fuses subject to ground motions and to develop an energy-based evaluation approach for evaluating the damage-control behavior of the system. First, the energy factor of steel MRF systems with fuses below the resilience threshold is derived utilizing the energy balance equation considering bilinear oscillators with significant post-yielding stiffness ratio, and the effect of structural nonlinearity on the energy factor is investigated by conducting a parametric study covering a wide range of parameters. A practical transformation approach is also proposed to associate the energy factor of steel MRF systems with fuses with classic design spectra based on elasto-plastic systems. Then, the energy balance is extended to structural systems, and an energy-based procedure for damage-control evaluation is proposed and a damage-control index is also derived. The approach is then applied to two types of steel MRF systems with fuses to explore the applicability for quantifying the damage-control behavior. The rationality of the proposed approach and the accuracy for identifying the damage-control behavior are demonstrated by nonlinear static analyses and incremental dynamic analyses utilizing prototype structures.

• Geomechanics and Engineering
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• v.14 no.5
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• pp.439-451
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• 2018

The stress path characteristics of surrounding rock in the formation of gob were analysed and the unloading was solved. Taking Chengchao Iron Mine as the engineering background, the model for analysing the instability of deep gob was established based on the mechanism of stress relief in deep mining. The energy evolution law was investigated by introducing the local energy release rate index (LERR), and the energy criterion of instability of surrounding rock was established based on the cusp catastrophe theory. The results showed that the evolution equation of the local energy release energy of the surrounding rock was quartic function with one unknown and the release rate increased gradually during the mining. The calculation results showed that the gob was stable. The LERR per unit volume of the bottom structure was relatively smaller, which mean the stability was better. The LERR distribution showed that there was main energy release in the horizontal direction and energy concentration in the vertical direction which meet the characteristics of deep mining. In summary, this model could effectively calculate the stability of surrounding rock in the formation of gob. The LERR could reflect the dynamic process of energy release, transfer and dissipation which provided an important reference for the study of the stability of deep mined out area.

• Asian Journal of Business Environment
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• v.4 no.2
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• pp.17-21
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• 2014

Purpose - The paper analyzes basic indicators characterizing the volume of energy sector activity in the Russian Federation, Privolzhsky Federal district, Republic of Tatarstan. Research design, data, and methodology - The study analyzed data from the Privolzhsky Federal district, specifically, industrial production volume, electricity production, energy consumption, energy-balance data, capital investments, and capital investment structure. An array of data has been investigated in recent years. The dataset's dynamics were analyzed in 1998. Fixed capital investment dynamics were studied in 1946 the figures were converted to a comparable form using the index method. Trends were analyzed using multivariate statistics methods and the Statgraphics software package. Results - Hypothesis 1. There are sectoral disproportions in energy flows,taking into account the volume of electricity production and consumption. Trends in electricity production in general coincide with industrial production volume trends. Energy flows have disparities in individual territorial units, and in general. Hypothesis 2. The degree of sectoral economic stability decreases with insufficient levels of investment in fixed capital energy organizations. Conclusions - Because totalelectricity production is largely determined by fixed capital investments, the study of their trends and patterns will coordinate efforts on investment operations in this area.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.3
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• pp.393-398
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• 2015

City or Community-scale Energy Management System(CEMS) is used to reduce the total energy consumed in the city by arranging the energy resources efficiently at the planning stage and controlling them economically at the operating stage. Of the operational functions of the CEMS, generation forecasting of renewable energy resources is an essential feature for the effective supply scheduling. This is because it can develop daily operating schedules of controllable generators in the city (e.g. diesel turbine, micro-gas turbine, ESS, CHP and so on) in order to minimize the inflow of the external power supply system, considering the amount of power generated by the uncontrollable renewable energy resources. This paper is written to introduce numerical models for photo-voltaic power generation prediction based on the weather forecasting information. Unlike the conventional methods using the average radiation or average utilization rate, the proposed models are developed for CEMS applications using the realtime weather forecast information provided by the National Weather Service.

• Journal of the Korean Solar Energy Society
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• v.31 no.2
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• pp.99-106
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• 2011

Since the solar energy resource is the main input for sizing any solar photovoltaic system, it is essential to utilize the solar radiation data as an application and development of solar energy system increase. It will be necessary to understand and evaluate the insolation data. The Korea Institute of Energy Research(KIER) has begun collecting horizontal global insolation data since May, 1982 at 16 different locations in Korea and for the more detailed analysis, images taken by geostationary satellite may be used to estimate solar irradiance fluxes at earth"s surface. It is based on the empirical correlation between a satellite derived cloud index and the irradiance at the ground. From the results, the measured data has been collected at 16 different stations and estimated using satellite at 23 different stations over the South Korea from 1982 to 2009. The Result of analysis shows that the annual-average daily global radiation on the horizontal surface is 3.56 kWh/ $m^2$/day and estimated solar radiation fluxes show reliable results for estimating the global radiation with average deviation of -7.27 to +3.65% from the measured values.

• Current Photovoltaic Research
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• v.10 no.1
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• pp.6-15
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• 2022

Climate change is among the most important issues facing mankind in modern society. However, global PV energy expansion has been driven mainly by OECD countries. We investigate the determinants of PV energy growth by panel data of selected OECD countries from 1991 to 2018. We investigate four categories of driving factors: socioeconomic, technological, country specific, and policy factors. The test results support that PV capacity growth is significantly driven by technology development and multidimensional environment policy factors. Socioeconomic factors such as CO₂, GDP, and electricity price are statistically significant on the growth of PV energy, too. Whereas, country-specific solar potential factor is the least related. As most of the socioeconomic factors are exogenous, we need to focus more on PV technology development and policy measures.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.581-586
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• 2002

Addition of steel fiber to shotcrete is to improve the brittleness of concrete. Quality of steel fiber reinforced shotcrete can be evaluated by quantitive analysis of toughness characteristics after cracking. The toughness characteristics can be expressed by absolute value of energy absorption capacity, non-dimensional toughness index related to the energy absorption capacity, and equivalent flexural strength at arbitrary deflection. In this study, merits and demerits of flexural toughness by RTA round panel of Australia and other specifications have been analyzed.

• KIEE International Transactions on Power Engineering
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• v.4A no.1
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• pp.6-10
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• 2004

This paper presents an assessment of the customer interruption costs using a macro economic methodology of Korean customers by cities and provinces. The customer interruption cost is considered a very useful index in quantifying reliability worth from a customer point of view. This paper reviews the methodology to evaluate the customer interruption costs and ratio to the average revenues per electric energy sold for public, service agriculture, fishery, mining, manufacturing and residential sectors by cities and provinces in Korea.