• Title/Summary/Keyword: LQ index

Search Result 39, Processing Time 0.029 seconds

A study on integrated guidance scheme for guided weapon system (유도무기를 위한 통합된 유도기법에 관한 연구)

  • 김병수;한형석;이장규;박성희;이재명;김삼수
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 1992.10a
    • /
    • pp.590-595
    • /
    • 1992
  • An integrated guidance scheme for guided weapon system is described in this paper. Against conventional guidance methods, this method combines an autopilot and a guidance law. The controller is designed using LQ regulator whose performance index is different from other optimal guidance laws. Since dynamics of the system is considered in the derivation, the controller performance is improved. By simulation, the suggested method shows better performance in minimum distance sense than conventional guidance schemes such as Bang Bang guidance or Pursuit Guidance. Since the suggested method provides smooth rudder deflection in contrast to the conventional method, the load on a energy source of the system can be greatly lessened.

  • PDF

Research on the Impact of Logistics Industry Efficiency and Agglomeration Effect on Import and Export Trade in Korea

  • Cheng, Wen-Si
    • Journal of Korea Trade
    • /
    • v.25 no.5
    • /
    • pp.93-109
    • /
    • 2021
  • Purpose - The logistics industry is often featured by its location relevance and industrial concentration. Industrial concentration is conducive to the effective transmission of information by reducing transaction costs and improving transaction efficiency, thus promoting the development of trade. The main purpose of this paper is to measure the spatial total factor productivity and location quotient of the logistics industry in Korea, and to study the impact of the logistics industry efficiency and agglomeration effect on import and export trade in Korea. Design/methodology - First, used the spatial stochastic frontier method to measure the spatial total factor productivity of the logistics industry in Korea, this serves as the efficiency index of the logistics industry in various regions of Korea. Second, calculated the location quotient (LQ) of the logistics industry to measure the industry's concentration degree. Third, employed a spatial econometric model to analyze the impacts of factors such as the efficiency and concentration levels of the logistics industry on import and export trade in Korea. Findings - This study's main findings can be summarized as follows: this study found that the overall efficiency of the logistics industry in Korea needs to be improved, even though it showed an upward trend in all regions of the country; Moreover, the agglomeration level of Korea's logistics industry needs to be improved; Finally, the positive spatial correlation and industrial agglomeration effect of Korea's logistics industry had a positive impact on the country's import and export trade. Originality/value - This study is innovative in terms of research perspective and methods. Most of the previous studies have measured the development level of the logistics industry using the logistics performance index (LPI), Fewer studies have assessed through the spatial total factor productivity and location quotient of the logistics industry in Korea to measure the efficiency index of the logistics industry in various regions of Korea and concentration degree, as well as there was almost no study on the impact of logistics industry efficiency and agglomeration effect on import and export trade in Korea. This study addresses this limitation by analyzing the impacts of the efficiency and agglomeration effect of the logistics industry on import and export trade in Korea.

An Analysis of the Port Competition Structure: Focusing on Import and Export Items of Ports in Western Coast Region (항만의 경쟁구조 분석에 관한 연구: 서해안권 항만 수출입품목을 중심으로)

  • Lee, Jin-Kyu;Yeo, Gi-Tae
    • Journal of Korea Port Economic Association
    • /
    • v.31 no.4
    • /
    • pp.75-89
    • /
    • 2015
  • This study examines 31 import and export cargo items handled in each port to investigate which items face the most competition among the ports and how many of them are transited to other ports. The study aims to suggest implications for the future port policy of Incheon Port. It was found that the volume concentration in the Western Coast region from 2005 to 2014 became increasingly decentralized. The decentralization began in earnest in 2009 in particular, and the value was 0.448 in 2014, indicating fierce competition among the regions. According to the static and dynamic positioning analyses results for Incheon Port, Pyeongtaek and Dangjin Port, and Gunsan Port, using BCG Matrix, the static positioning analysis showed that Incheon Port belongs to the 3rd quadrant (Cash Cows), Pyeongtaek and Dangjin Port belongs to the 2nd quadrant (Question Marks), and Gunsan Port belongs to the (Dogs) group. This implies that Incheon Port has maintained its position with large shares compared to those of other ports, despite its low growth rate. However, the market position and growth rate of Incheon Port decreased according to the dynamic positioning analysis results. The shift-share analysis results indicated that the volumes of Incheon Port and Gunsan Port were shifting to Pyeongtaek and Dangjin Port. Moreover, the ratio of absolute growth to potential growth of Incheon Port and Gunsan Port turned out to be significantly lower than that of Pyeongtaek and Dangjin Port, implying that Incheon Port and Gunsan Port are declining as compared to Pyeongtaek Port and Dangjin Port. According to the LQ index analysis results, specialized items from Incheon Port that do not overlap with other ports included the following ten items: meat, fish and crustaceans, bituminous coals, crude oil and petroleum, petroleum-refined products, plastic rubber and products, textiles, nonferrous metal and products, electric machinery, and aircrafts and ships. In particular, it was confirmed that the bulk cargo of Incheon Port was actually shifting to Pyeongtaek and Dangjin Port following the policy of re-establishing port functions.

The Effect of Liquidity, Leverage, and Profitability on Firm Value: Empirical Evidence from Indonesia

  • JIHADI, M.;VILANTIKA, Elok;HASHEMI, Sayed Momin;ARIFIN, Zainal;BACHTIAR, Yanuar;SHOLICHAH, Fatmawati
    • The Journal of Asian Finance, Economics and Business
    • /
    • v.8 no.3
    • /
    • pp.423-431
    • /
    • 2021
  • This study aims to examine the effect of liquidity, activity, leverage, and profitability on firm value, as well as the effect of disclosure of corporate social responsibility (CSR), which in this study is a moderator and company size as a control variable. The sampling technique used in this study is a purposive sampling method with certain criteria, to obtain a sample of 22 LQ45 index companies listed on the Indonesia Stock Exchange in 2014-2019. The data analysis method in this study used was the Multiple Linear Regression Analysis with the SPSS 18 Program. The results show that the ratios of liquidity, activity, leverage, and profitability are significant to firm value in accordance with the initial hypothesis of the study. Corporate Social Responsibility (CSR) plays a role as a moderating variable and company size variable as a control variable on the effect of financial ratios (liquidity, activity, leverage, and profitability) on firm value. The implication of this research is that CSR has a very important role in increasing company value. To attract more investors, companies must pay attention not only to financial performance but also to social performance. Large-scale companies tend to do more CSR so that the company value will increase.

Determination of optical constants for organic light emitting material of Alq3 using Forouhi-Bloomer dispersion relations (포로히-블루머(Forouhi-Bloomer) 분산식을 이용한 유기발광물질 Alq3의 광학 상수 결정)

  • 정부영;우석훈;이석목;황보창권
    • Korean Journal of Optics and Photonics
    • /
    • v.14 no.1
    • /
    • pp.1-7
    • /
    • 2003
  • We determined the optical constants of organic light emitting material of Alq$_3$ in a spectral range between 1.5 and 6 eV using the physical model introduced by Forouhi and Bloomer[Phys. Rev. B 34, pp. 7018-7026, 1986.]. The initial parameters of $A_i,\;B_i,\;C_i$ of Forouhi-Bloomer dispersion relations were determined from the absorption peaks and widths of absorption spectra of the Alq$_3$ film. The refractive index of substrate, a fused silica, is derived from the Sellmeier equation with the measured transmittance and reflectance spectra. Then, the complex refractive index and thickness of the Alq$_3$ film were calculated by use of a nonlinear least square fitting program with the Forouhi-Bloomer dispersion relation and the measured transmittance and reflectance spectra.

A study on the competitiveness and analysis of research and development cluster in Seoul Seocho region - competitiveness and potential infra of Yangjae R&D cluster (서울시 서초구의 클러스터경쟁력 분석에 관한 연구: 양재 R&D 클러스터 조성을 중심으로)

  • Kim, Yong-Hwan;Lim, Hee-Jung;Choi, Young-Suk;Kim, In-Jung
    • Journal of the Korean Academic Society of Industrial Cluster
    • /
    • v.4 no.1
    • /
    • pp.14-50
    • /
    • 2010
  • This study focused on the competitiveness analysis of industrial cluster using econometric method and competency analysis method to measure the situation of Seocho-gu industrial cluster and Yangjae R&D cluster at Seoul. The econometric method used the data such as the number of firms, the number of employee, GRDP. The competency analysis method measured the level of agglomeration of cluster for years through LQ(Location quotient) index. In addition, the characteristics and structure of each industry in Secho-gu and Yangjae-dong R&D cluster. The circumstance of location and business, the competency of potential ability of industries were analysed by SWOT. In sum, this study has the following conclusion. First, Seocho-gu and Yangjae-dong region has an advantage in the circumstance for R&D related industry and man power. Second, Seocho-gu and Yangjae-dong region has a good potential for development in R&D related industries. These region has a good relationship the four major R&D related industry of Seoul. Third, these region also has a advantage in the potential development of R&D related researchers in the corresponding industries.

  • PDF

Calculation of the Peak-hour Ratio at Urban Railway Stations Reflecting Passenger Demand Pattern and Land Use Inventory - A Case of Seoul - (승객 수요 패턴과 역세권의 토지이용 특성을 반영한 도시철도역 첨두시간 집중률 산정 - 서울시를 대상으로 -)

  • Jang, Sunghoon;Kim, Hyo-Seung;Lee, Chungwon;Kim, Dong-Kyu
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.33 no.4
    • /
    • pp.1581-1589
    • /
    • 2013
  • The aim of this study is to suggest a methodology for calculating the peak-hour ratio of passengers at urban railway stations by reflecting the characteristics of passenger demand patterns and the land use inventory of stations. To achieve this, urban railway stations in Seoul are divided into three groups by using factor analysis and cluster analysis. For each station group, we calculate five and four variables related to the passenger demand patterns and the land use inventory of stations, respectively, as well as the peak-hour ratios of passengers. Among these nine variables, average daily passengers and the location quotient (LQ) index for business services are selected as the classification criteria for station groups based on statistical tests. Using the two variables, a group allocation process is suggested to estimate the peak-hour ratio of passengers for a newly-constructed station. Evaluation results based on thirteen stations show that the proposed methodology produces lower errors than the currently-used guideline does. The results of this study contribute to establishing efficiently construction and operation plans for newly-constructed stations.

A Study on the Changes in Specialization Degree and Cargo Volume by Cargo Type in Major Ports in Korea (우리나라 주요항만의 품목별 특화도와 물동량의 변동에 관한 연구)

  • Lee, Choong-bae;Su, Miao;Liu, Yanfeng
    • Journal of Korea Port Economic Association
    • /
    • v.37 no.1
    • /
    • pp.103-119
    • /
    • 2021
  • Ports in Korea have been increasing in terms of volume while they have performed functions and roles such as industrial ports in promoting industries of their hinterlands as well as commercial ports supporting imports and exports. Nevertheless, specialization degree is different from port to port by cargo type and the changes in cargo volume. This study aims to analyze the structural changes and the degree of concentration and specialization by cargo type and port between 2001 and 2020. Top 10 ports were analyzed in terms of traffic volume by categorizing liquid, dry, general cargo and containers. HHI(Herfindahl-Hirschman Index), LQ(Location Coefficient), and shift-share analysis were employed in order to identify the degree of concentration, specialization and changes in cargo volume by port and cargo type. As a result of the analysis, the degree of port concentration and specialization for each cargo of 4 categories have maintained a high level, and no significant difference were found in fluctuations over the past 20 years. As a result of calculating the flucation of cargo volume through the shift-share analysis, the growth rate of liquid cargo was high in Yeosu Gwangyang Port, Pyeongtaek Dangjin Port in dry cargo, and Busan Port in general cargo and container ports. The result implies that it is not expected that the structural changes including degree of cargo concentration, specialization and relative fluctuation of cargo volume is significant in Korean ports in the future since the effects of economies of scale and clustering were achieved to the great degree.

A Study on the Regional Variation of Tenancy System in Later Yi-Dynasty in Korea (조선(朝鮮) 후기소작(後期小作) 형태(形態)의 지역적(地域的).차이(差異)에 관(關)한 연구(硏究))

  • Kim, Ki-Hyuk
    • Journal of the Korean association of regional geographers
    • /
    • v.2 no.2
    • /
    • pp.1-8
    • /
    • 1996
  • The purpose of this study is to analyse the regional variation of tenancy system in later Yi-Dynasty in Korea. Materials for the analysis are acquired through materials(韓國土地農産調査報告), published in 1905 and agricultural census published in 1912. For the identification of difference of tenancy system between agricultural region, regionalization are conducted through by crop combination. Crop combination structure, using rank of LQ index, was clustered into five generic lesions through cluster analysis. In these contexts, this study has come to following conclusions. There are three types of tenancy system in materials; (1) Doji(賭地) system of which landrent was 1/3 agricultural products. Tenant healed the land tax and seeds. (2) Byoengjak(竝作) system of which landrent was 1/2 agricultural products. Landlords healed the land tax and seeds (3) Jeongaek(定額法) system of which landrent was fixed without relation to annual products. But through the analysis of relationship between agricultural region and tenancy system, a new tenancy system could be identified : Byeongjak(竝作) II system. In this system, landrent was 1/2 of agricultural products, but landlord and tenant shared the landtax and seed in common. In the distribution of these systems, relationship between tenancy system and agricultural regions could be identified. Doji system was distributed in the regions where rice and double cropping was specialized. But Byoeongjak(竝作) system was distributed in the regions where upland crops are specialized and ratio of Paddy field is comparatively low. Especially new types were emenged where ratio of paddy field was very low. These show that increase of productivity of land didn't induce the development of the right of ownership in land. The development of ownership was emerged only on the rice paddy fields. Barley cultivated through double-cropping passed into tenant's possessions. So nominal landrent in paddy field seemed to be raised, but actual landrent was maintained about 1/3 of Products through double cropping. On the contrary, rights of cultivation is developed through double cropping. As double cropping is developed, competition on paddy field between tenants was intensified. Consequently nominal land rent of Paddy fields should be raised.

  • PDF