• International journal of advanced smart convergence
• /
• 제11권2호
• /
• pp.171-184
• /
• 2022

The purpose of this paper is output oriented, in order to maximize the output level of sustainable development efficiency of foreign trade in western China with limited input. This paper adopts the relevant input-output indicators of sustainable foreign trade development of 11 provinces and cities in western China from 2016 to 2020, and uses DEA model to measure their technical efficiency, pure technical efficiency and scale efficiency. Malmquist index was used to calculate the total factor productivity change index of each province in western China from 2016 to 2020. We found that, on the whole, the average values of technical efficiency, pure technical efficiency and scale efficiency of provinces and cities in western China from 2016 to 2020 are greater than 0.8, indicating that the western region has high technical efficiency, relatively high management and institutional level and high existing scale level. Scale efficiency is lower than pure technical efficiency on the whole, indicating that the current sustainable development efficiency of foreign trade in western China is mainly limited by its scale level. The technological progress index is higher than the technological efficiency change index, indicating that the total factor productivity of the sustainable development of foreign trade in western China is mainly driven by technological progress and more influenced by external factors. We think the conclusion of this study can provide important reference information for the sustainable development of foreign trade of provinces and cities in western China.

• Journal of Forest and Environmental Science
• /
• 제24권3호
• /
• pp.155-158
• /
• 2008

Site index is the essential tool for forest management to estimate the productivity of forest land Generally, site index equation is developed and used by relationship between stand age and dominant tree heights. However, there is a limit to use the site index equation in the application of variable ages, environmental influence, and estimation of site index for unstocked land. Therefore, it was attempted to develop a new site index equations based on various environmental factors including site and topographical variables. This study was conducted to develop regional site index equations based on the relationship between site index and soil factors for Pinus densiflora. Environmental factors that obtained from GIS application, were selected by stepwise-regression. Site index Equation was estimated by multiple regression from selected factors. Four environmental factors were selected in the final site index equations by stepwise regression. It was observed that coefficients of determination for site index equations were ranged from 0.34 which seem to be relatively low but good enough for estimation of forest stand productivity. The site index equations developed in this study were also verified to be useful by three evaluation statistics such as model's estimation bias, model's precision and mean square error type of measure.

• 한국농림기상학회지
• /
• 제8권2호
• /
• pp.97-106
• /
• 2006

Site index is an essential tool to estimate forest productivity. Generally, a site index equation is developed and used from the relationship between stand age and dominant tree heights. However, there is a limit to the use of the site index equation in the application of variable ages, environmental influence, and estimation of site index for the unstocked forest. Therefore, it has been attempted to develop a new site index equation based on various environmental factors including site, climate, and topographical variables. This study was conducted to develop a site index equation based on the relationship between site index and environmental factors for the species of Pinus koraiensis in Yangpyung-Gun, Gyunggi Province. The influence of climatic factors (temperature and solar irradiation ratio), topographical factors (elevation, slope, ratio of slope to valley and aspect) and soil profiles (soil depth by layer and soil consistency) on site index were evaluated by multiple regression analysis. Five environmental factors were selected in the final site index equation for Pinus koraiensis. The site index equation developed in this study was also verified by three evaluation statistics: model's estimation bias, model's precision, and mean square error of measurement. Based on the site index equation, the number of productive areas for Pinus koraiensis were estimated by applying GIS technique to digitized forest maps. In addition, the distribution of productive areas was compared with the areas of current distribution of Pinus koraiensis. It is expected that the results obtained in this study could provide valuable information about the amount and distribution of productive areas for Pinus koraiensis reforestation.

• 한국IT서비스학회지
• /
• 제12권4호
• /
• pp.187-204
• /
• 2013

In this study, we developed a comprehensive model to measure the National Information Security Level based on PRM framework. The proposed model reflected a rapidly changing technology environments such as social network service, mobile devices, and etc. This new model consists of three layers:Infrastructure Layer, the Action Layer and the Performance Layer, and there are 16 sub-indexes under the 3 layers. To develop new model and sub-indexes for measuring the National Information Security Level, much amounts of documents related to security indexes or deliberation criteria and security guidelines from international organization were reviewed and then most probable index pool were composed. The Index pool were verified by expert group consisting of professors and specialists. Through five times of screening and having an evaluation review, 16 sub-indexes were deduced and then Delphi and AHP have been conducted to obtain validity and objectiveness of the indexes. Thus the new proposed national information security index will show more exact national information security level and we expect that the indexes give much implications for establishing information protection policy.

• 품질경영학회지
• /
• 제35권4호
• /
• pp.26-37
• /
• 2007

The demand of ubiquitous home network system is rapidly increasing in Korea as each construction enterprise makes a huge effort to introduce it to apartment complex. However, the design of home network system is rather technology oriented than the customer focused. Lack of knowledge about customer needs is an obstacle in spreading the ubiquitous home network system to the market regardless of technology development. In this paper, we propose a HCSI(customer satisfaction index for home network system) using an SEM(structural equation model) where structural relationship among several factors influential on users' satisfaction is considered. This model enables to calculate the satisfaction index for target customer group so that one can provide necessary feedback information for improvement of the home network system used for each group.

• ETRI Journal
• /
• 제30권5호
• /
• pp.634-643
• /
• 2008

One of the ubiquitous technology fields that have received the most attention recently from technology communities worldwide is mobile radio frequency identification (RFID). Mobile handsets loaded with RFID readers enable the identification and retrieval of information on RFID tagged objects. In Korea, a variety of mobile RFID services are currently being piloted, and their commercial roll-out looks imminent. The goal of this study is to propose, ahead of the commercial launch of mobile RFID services, a customer satisfaction index (CSI) model for this service category and to then measure the CSI to derive practical implications for their providers and pointers related to the improvement of service. A web survey was conducted on Korean mobile phone subscribers who had participated in a mobile RFID pilot program. Using the results of this survey, we tested the CSI model and its hypotheses by employing a partial least-squares-based structural equation model analysis and calculated the index. We further conducted an importance-performance analysis in order to provide insights that may be useful for improving the quality of mobile RFID services.

• 한국정보과학회논문지:데이타베이스
• /
• 제31권1호
• /
• pp.48-60
• /
• 2004

정보 표현의 기본 단위인 엘리먼트로 구성되는 XML 문서 내에서 동적으로 구조 변경이 이루어진다. 이때 XML 문서의 구조변경은 빠른 검색을 위해 기존의 색인 구조 정보의 변경 없이 효율적으로 처리되어야 한다. 이를 위해 본 논문에서는 XML 문서의 구조 변경 시 기존의 색인 구조에 효율적으로 수용될 수 있는 동적 색인 모델을 제안한다. 제안하는 동적 색인 모델은 다양한 구조 검색을 지원하기 위한 구조 정보 표현 방법과 효율적인 구조 검색을 지원하기 위한 동적 색인 구조로 구성된다. 제안하는 색인 기법이 기존의 동적 색인을 지원하는 기법보다 내용 색인, 구조 색인, 애트리뷰트 색인 측면에서 우수함을 성능 평가를 통해 보인다.

• The Journal of Asian Finance, Economics and Business
• /
• 제7권9호
• /
• pp.135-145
• /
• 2020

This paper provides the practical application of a linear shrinkage framework on Vietnam stock market. The cumulative data points observed in this analysis are 468 weeks from January 2011 to December 2019. All the companies listed on Ho Chi Minh City Stock Exchange (HOSE), except the companies under two years period from Initial Public Offering (IPO), are considered. The cumulative number of stocks picked is therefore 350 companies. The VNINDEX, which is the Vietnam Stock Index, is used as a reference index for shrinking to a single-index model. The empirical results show that the shrinkage of covariance matrix for portfolio optimization gives the promising results for the investors on Vietnam stock market. The shrinkage method helps the investors to produce the optimal portfolio in the sense of having higher profit with lower levels of risk compared to the portfolio of the traditional SCM method. Moreover, the portfolio turnover of shrinkage method is always kept at low magnitudes, and this makes the shrinkage portfolios save much transaction costs and reduce the liquidity risks in the trading process. In addition, the ability of shrinkage method in making profit is once again confirmed by the Alpha coefficient that achieves a high positive value.

• 한국자동차공학회논문집
• /
• 제12권5호
• /
• pp.136-145
• /
• 2004

In companion paper, the composition and structure of the traffic environment is derived. Rules to regulate agent behaviors and the frameworks to communicate between the agents are proposed. In this paper, the model of a driver agent which controls a vehicle agent is constructed. The driver agent is capable of having different driving styles. That is, each driver agent has individual behavior settings of the yielding index and the passing index. The yielding index can be defined as how often the agent yields in case of lane changes, and the passing index can be defined as how often the agent passes ahead. According to these indices, the agents overtake or make their lanes for other vehicles. Similarly, the vehicle agents can have various vehicle dynamic models. According to their dynamic characteristics, the vehicle agent shows its own behavior. The vehicle model of the vehicle agent contains the nonlinear subcomponents of engine, torque converter, automatic transmission, and wheels. The simulation has proceeded for an interrupted flow model. The result has shown that it is possible to express the characteristics of each vehicle and its driver in a traffic flow, and that the change of the traffic state is closely related with the distance and the signal delay between intersections. The system developed in this paper shows the effectiveness and the practical usefulness of the traffic simulation.

• 한국유기농업학회지
• /
• 제30권4호
• /
• pp.499-516
• /
• 2022

Blueberry producers' management is failing as a result of the price decline caused by an increase in blueberry imports and the accompanying deterioration in management. Consequently, an endeavor was undertaken to verify the measurement and impact from the standpoint of efficiency and productivity of blueberry management, and to offer an indication of management improvement through analysis. Using the Rural Development Administration's income survey data, the data for twenty-four blueberry farms was analyzed. First, the management effectiveness of blueberry cultivators was evaluated. Using the CCR model (0.7297) and the BCC model (08148), the efficiency of a farm was examined. When the efficiency is one, CCR is ten and BCC is fifteen, and in overall, it was found to be ineffective, the efficiency declined from 2018 to 2019, but climbed again in 2020, according to the annual analysis. The MPI index was then used to examine productivity. T2's MPI index was 1.3338, whereas T3's MPI index was 0.8896, demonstrating a considerable decline in TC. This indicates that technological progress is not being accomplished, necessitating the need for countermeasures. In order to improve the management efficiency of blueberry producers, it is necessary to reduce costs and improve receivable prices through producer organization, and to actively introduce new technologies.