• Management & Information Systems Review
• /
• v.29 no.2
• /
• pp.1-25
• /
• 2010

This study attempted to empirically test the determinants of stock returns in Korean stock market applying multi-factor model proposed by Haugen and Baker(1996). Regression models were developed using 16 variables related to liquidity, risk, historical price, price level, and profitability as independent variables and 690 stock monthly returns as dependent variable. For the statistical analysis, the data were collected from the Kis Value database and the tests of forecasting power in this study minimized various possible bias discussed in the literature as possible. The statistical results indicated that: 1) Liquidity, one-month excess return, three-month excess return, PER, ROE, and volatility of total return affect stock returns simultaneously. 2) Liquidity, one-month excess return, three-month excess return, six-month excess return, PSR, PBR, ROE, and EPS have an antecedent influence on stock returns. Meanwhile, realized returns of decile portfolios increase in proportion to predicted returns. This results supported previous study by Haugen and Baker(1996) and indicated that firm-characteristic model can better predict stock returns than CAPM. 3) The firm-characteristic model has better predictive power than Fama-French three-factor model, which indicates that a portfolio constructed based on this model can achieve excess return. This study found that expected return factor models are accurate, which is consistent with other countries' results. There exists a surprising degree of commonality in the factors that are most important in determining the expected returns among different stocks.

• Research in Community and Public Health Nursing
• /
• v.9 no.1
• /
• pp.232-241
• /
• 1998

음주습관과 심혈관계 질환 위험요인사이의 관련성을 파악하기 위하여, 1996년 한국 경북에 있는 도시지역 한 철강회사에서 40-50대(40-59세) 남자 근로자 3444명으로부터 공복시 혈액을 10m1 채취하여 혈청지질, 혈당, Uric acid를 측정하고 신장, 체중, 혈압(10-20분 휴식후 측정)과 EKG를 측정하였다. 과거병력, 현재 건강상태, 음주량과 기간 및 음주종류를 포함한 생활습관, 흡연량/일, 운동시간/주 등의 설문지를 작성하였다. 알콜 소비량은 양-빈도의 Index에 의해 측정되었다. 한국 중년 남자에 대한 음주량, 음주기간, 알콜종류등에 따른 심혈관계 질환의 위험요인 유무 정도를 알아보기 위해, 비음주자를 기준으로하여 비교대상군은 금주자와 음주량(2군) 등에 의해 3군으로 분류하였으며, 음주기간에 따른 심혈관계 질환의 위험요인 유무정도를 알아보기 위해 비음주자을 기준으로하여 비교 대상군은 금주자와 음주기간(4군)에 따라 5군으로 분류하였다. 알콜종류에 따른 심혈관계 질환의 위험요인 유무정도를 알아보기 위해 비음주자을 기준으로하여 비교 대상군은 금주자와 음주알콜종류(3군)에 따라 4군으로 분류하였다. 심혈관계 질환 위험요인은 기준되는 범주를 2개(Table 1)로 분류하여 2*2표를 이용하여 odds ratio(dummy variable로 처리), ${\beta}$-coefficient와 표준오차를 이용해서 신뢰구간(95% C.I.)을 구하여 유의성 검정을 하였다. 금주자의 정의는 과거 3달 이상 술을 마시지 않는 사람을 말한다. 연구 집단의 평균 연령은 $44.4{\pm}3.9$세 이며, 비음주자는 649명으로 18.9%, 금주자는 70명(2.0%)이며 음주자는 2725명(79.1%)이다. 음주자중 에타놀 섭취를 평균 100.5g/주(median) 미만인 군은 1239명으로 연구집단 3444명중 35.7%이며, 평균 100.5g/주(median) 이상 음주군은 1276명으로 44.5%이었다. 3444명중 1532명(44.5%) 이 맥주와 소주를 섞어서 마시는 사람이었다. 음주 양에서, 연령, 흡연 양, 흡연 기간, 운동, 음주기간, 알콜종류 등을 통제하여 logistic regression한 결과, 비음주자에 비해 중정도 음주자(${\ge}$100.5gm/week ethanol)의 확장기 혈압의 Odds ratio는 1.33배로 유의하게 높았다(P<0.05). 다른 요인들은 통계적으로 유의한 차이를 보이지 않았다. 알콜종류에서도 연령, 흡연 양, 흡연 기간, 운동, 음주양, 음주기간, 등을 통제한, 비음주자에 비해 맥주와 소주를 섞어 마시는 음주자의 확장기 혈압의 Odds ratio는 1.38배로 유의하게 높았다(P<0.01). 다른 요인들은 통계적으로 유의한 차이를 보이지 않았다. 반면에 음주 습관 중 음주기간에서는 연령, 흡연양, 흡연 기간, 운동, 음주양, 알콜종류 등을 통제한 logistic regression 분석 결과 유의한 차이를 보인 것은 없었다. 그러나 음주기간과 심혈관계 질환 위험요인중 수축기와 확장기 혈압과의 관계는 J 모양을 나타내었다 . 수축기 혈압의 금주자군은 비차비가 1.0보다 약간 낮고(Odds ratio=0.88) 음주기간이 2-10년인 군의 Odds ratio=1.14, 음주기간이 11-20 년인군의 Odds ratio =1.18, 21년 이상인 군의 Odds ratio=1.20로 비음주자의 odds ratio=1에 비해 점차적으로 위험이 높아졌다. 확장기 혈압의 금주자군은 비차비가 1.0보다 약간 낮고(Odds ratio=0.91), 음주기간이 1년 이하인 군의 Odds ratio=1.18, 음주기간이 2-10 년인 군의 Odds ratio=1.23, 음주기간이 11-20 년인 군의 Odds ratio=1.27, 21년 이상인 군의 Odds ratio=1.27로 비음주자의 odds ratio=1에 비해 점차적으로 위험이 높아졌다.

• KDI Journal of Economic Policy
• /
• v.12 no.1
• /
• pp.111-125
• /
• 1990

For the last several years, considerable criticism has been leveled against Korea's exchange rate management. While Korea was designated a currency manipulator by the U.S., domestically it is often complained that the won/dollar rate did not adequately reflect changes in Korea's export competitiveness and fluctuations in the exchange rates of major currencies. In view of this situation, Korea changed its exchange regime at the beginning of March this year from the dual currency basket system to a more flexible one, called a "market average rate regime". Under this new regime, the won rate is determined in the exchange market based upon the supply of and demand for foreign exchange and is allowed to freely fluctuate each day within a + 0.4 % range. This paper, first, seeks to evaluate Korea's exchange rate management under the dual basket regime of the 1980s, and then to construct an optimal currency basket for the won which could provide a proper indicator for exchange market intervention under the new market average rate regime. The analysis of fluctuations in the real effective exchange rate (REER) of the won indicates that the won rates in the 1980s failed not only to offset changes in relative prices between home and trading partner countries, but also to properly respond to variations in major exchange rates as further evidenced by sizable fluctuations in the nominal effective rates of the won. In other words, the currency basket regime which was adopted in 1980 for the stabilization of the REER of the won has not been operated properly, mainly because authorities often resorted to policy considerations in determining the won's rate. In the second part of the paper, an optimal currency basket for Korea is constructed, designed to minimize the fluctuations in the REER of the won without including policy considerations as a factor. It is recognized, however, that both domestic and foreign price data are not available immediately for the calculation of the REER. For this problem, the approach suggested by Lipschitz (1980) is followed, in which optimal weights for currencies in the basket are determined based upon the past correlation between price and exchange rates. When the optimal basket is applied to Korea since the mid-80s, it is found that the REER of the won could have been much more stable than it actually was. We also argue for the use of variable weights rather than fixed ones, which would be determined by the changing relationship between exchange rates and relative prices. The optimal basket, and the optimal basket exchange rate based on that basket, could provide an important medium- or long-term reference for proper exchange market intervention under the market average rate regime, together with other factors, such as developments in the current account balance and changes in productivity.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.45 no.3
• /
• pp.92-106
• /
• 2017

This paper examines the validity of issuing municipal bonds for land compensation of long-term unexecuted urban parks and greenbelts. Then it suggests that municipal bonds should be issued for compensation priority areas with high rising prices. By conducting correlation analysis and PLS(Partial Least Squares) regression for 32 long-term unexecuted urban parks and greenbelts, the factors were identified that affected 'rising prices of IAPLP(Individually Announced Public Land Price) after seven years'. According to the analysis results, Variable Importance in the Projection in PLS regression was higher in 'IAPLP of base year(1.919)' and 'Accumulated rising Rates of average IAPLP in the borough(1.176).' The implications of this study are as follows. In Seoul, the accumulated rising rates of average IAPLP over the past 12 years is higher than the accumulated interest rates for seven years of urban planning facility bonds, which means that IAPLP have risen more than the interest payments due to the issuance of municipal bonds. In addition, since the actual compensation is three times that of IAPLP, it is judged that the land price is actually much higher than the interest payments. This shows that issuing municipal bonds and preferentially compensating for areas like high rising land prices can increase the economic efficiency of the budget execution. Also, for economic efficiency of budget execution, it is necessary to propose an 'area with high IAPLP' or 'a part in the borough with high rising rate of average IAPLP,' which is expected to have a high rising land price as criteria for compensation priority areas. In the future, when issuing municipal bonds to compensate long-term unexecuted urban parks and greenbelts, variousresearch on financing for municipal bonds repayment should be conducted.

• Strategy21
• /
• s.38
• /
• pp.112-162
• /
• 2015

This study began to confirm or review the balance of power theory by applying scientific methods through experiential cases. Though there are several kinds of national power, this study supposes military power as a crucial power when it comes to war and peace. This research covered balance and imbalance through comparing relative military power between nations or nations' group. Comparison of relative military power can be achieved by statistically processing the values of which has been converted into the standard variables in same domain, then calculating the values of nation's power which has been synthesized different experiential factors. In addition, the criteria of experiential experiment is highly dedicated to European countries, USA, Japan prior to 1st and 2nd World War, as well as USA, Soviet Union and North East Asia during Cold War era. In addition, the balance of power theory has been redefined to review the action of the state upon the changes of power as mentioned in the theory. To begin with, the redefined theory states that relative level of military power between nations defines the consistency of peace and balance of power. If military power is enough to be on the range of level required to keep the power in equilibrium, peace and balance can be achieved. The opposite would unbalance the military power, causing conflicts. While the relative military level between nations change, nations seek to establish 'nations group' via military cooperation such as alliance, which also shift relative military power between nations group as well. Thus, in order to achieve balance of power, a nation seeks to strengthen its military power(self-help), while pursuing military cooperation(or alliance). This changes relative military power between nations group also. In other words, if there exists balance of power between nations, there is balance of power between nations group as well. In this theory, WWI and II broke out due to the imbalance of military force between nations and nations group, and reviewed that due to the balance of military force during the Cold War, peace was maintained. WWI was resulted from imbalance of military cooperation between two powerful states group and WWII was occurred because of the imbalance among the states. Peace was maintained from cooperation of military power and balance among the states during the Cold War. Imbalance among continental states is more threatening than maritime states and balance of power made by army force and naval force also is feasible. Also the outcomes of two variables are found military power balanced ratio of military power for balance is 67% when variable ratio of balance is 100% and standard value for balance is 0.86. Military power exists in a form of range. The range is what unstabilized the international system causing nations to supplement their military powers. These results made possible the calculation and comparison between state's military power. How balance of power inflicted war and peace has been studied through scientific reviews. Military conflict is highly possible upon already unbalanced military powers of North East Asian countries, if the US draws its power back to America. China and Japan are constantly building up their military force. On the other hand, Korean military force is inferior so in accordance to change of international situation state's survival could be threatened and it is difficult to achieve drastic increase in military force like Germany did. Especially constructing naval force demands lots of time; however but has benefit that naval force can overcome imbalance between continental states and maritime states.

• Journal of the Korean earth science society
• /
• v.41 no.5
• /
• pp.469-477
• /
• 2020

Salinity is not only an important variable that determines the density of the ocean but also one of the main parameters representing the global water cycle. Ocean salinity observations have been mainly conducted using ships, Argo floats, and buoys. Since the first satellite salinity was launched in 2009, it is also possible to observe sea surface salinity in the global ocean using satellite salinity data. However, the satellite salinity data contain various errors, it is necessary to validate its accuracy before applying it as research data. In this study, the salinity accuracy between the Soil Moisture Active Passive (SMAP) satellite salinity data and the in-situ salinity data provided by the Ieodo ocean research station was evaluated, and the error characteristics were analyzed from April 2015 to August 2020. As a result, a total of 314 match-up points were produced, and the root mean square error (RMSE) and mean bias of salinity were 1.79 and 0.91 psu, respectively. Overall, the satellite salinity was overestimated compare to the in-situ salinity. Satellite salinity is dependent on various marine environmental factors such as season, sea surface temperature (SST), and wind speed. In summer, the difference between the satellite salinity and the in-situ salinity was less than 0.18 psu. This means that the accuracy of satellite salinity increases at high SST rather than at low SST. This accuracy was affected by the sensitivity of the sensor. Likewise, the error was reduced at wind speeds greater than 5 m s^-1. This study suggests that satellite-derived salinity data should be used in coastal areas for limited use by checking if they are suitable for specific research purposes.

• Korean Journal of Ecology and Environment
• /
• v.46 no.2
• /
• pp.145-153
• /
• 2013

It is a global trend that the water management policy is shifting from a water quality-oriented assessment to the aquatic ecosystem-based assessment. The majority of aquatic ecosystem assessment systems were developed solely based on physicochemical factors (e.g., water quality and bed structure) and a limited number of organisms (e.g., plankton and benthic organisms). Only a few systems use plants for a health assessment, although plants are sensitive indicators reflecting long-term disturbances and alterations in water regimes. The development of an assessment system is underway to evaluate and manage lakes as ecosystem units in the Korean Ministry of Environment. We reviewed the existing multivariate health assessment methods of other leading countries, and discussed their applicability to Korean lakes. The application of multivariate assessment methods is costly and time consuming, in addition to the correlation problem among variables. However, a single variable is not available at this moment, and the multivariate method is an appropriate system due to its multidimensional evaluation and cumulative data generation. We, therefore, discussed multivariate assessment methods in three steps: selecting metrics, scoring metrics and assessing indices. In the step of selecting metrics, the best available metrics are species-related variables, such as composition and abundance, as well as richness and diversity. Indicator species, such as sensitive species, are the most frequently used in other countries, but their system of classification in Korea is not yet complete. In terms of scoring metrics, the lack of reference lakes with little anthropogenic impact make this step difficult, and therefore, the use of relative scores among the investigated lakes is a suitable alternative. Overall, in spite of several limitations, the development of a plant-based multivariate assessment method in Korea is possible using mostly field research data. Later, it could be improved based on qualitative metrics on plant species, and with the emergence of further survey data.

• Journal of Animal Environmental Science
• /
• v.8 no.1
• /
• pp.9-16
• /
• 2002

This study was conducted to develope the new solid separating system which can be efficiently and economically removed the solid parts in high pollutants concentration of pig slurry. The pollutants concentration, BOD$_{5}$ , COD and SS of the slurry used in this study was 15,990($\pm$2,389)mg/l, 20,004($\pm$5,512)mg/l and 26,486($\pm$5,935)mg/l, respectively. After removal of solid part in slurry, the pollutants concentration, BOD$_{5}$, COD and SS was change into 5,617($\pm$690)mg/l, 5,553($\pm$633)mg/land 1,456($\pm$341)mg/l, respectively in the Fixed biological membrane tank. The reduction of the pollutants concentration of suspend liquid through membrane will be allowed to greatly improve the water purification by an Activated sludge method. This separating system consisted of a temporary storage, a circulating tank and a Fixed Biological membrane tank. A temporary storage which has a draining system of screw type and an aeration device played a tremendous role in draining the solid by filled an aeration of 0.3 l/min. A Fixed Biological membrane tank of which a styrofoam filled in a 2/3 volume as a Biological media was fixed by a stainless steel net (pore size : 0.5mm) to separate the liquid layer of influx in them. The separating system efficiency factors were the speed of screw motor, cycle number of slurries in a circulating tank and moisture contents of solid effluent through the screw path. Although the pollutants concentration was very variable in temporary storage, the final concentration of $BOD_5$ and SS, except COD of the suspended liquid in a Fixed biological membrane were not different regardless of cycle number of a circulating tank. Moisture contents of effluent from temporary storage was 73% under the speed 1 ppm of screw motor and 62% under the 1/4rpm of it.

• Journal of Life Science
• /
• v.22 no.5
• /
• pp.642-649
• /
• 2012

The southern coast of Korea is important for the ark shell ($Scapharca$ $broughtonii$) aquaculture, but the productivity was rapidly reduced during the previous decade by mass mortality. To overcome this economic loss, investigations only focused on environmental factors, and microbiological researches were performed insufficiently. In this study, two sites (Gangjin and Jinhae bay) were selected for their high and low rate of mortality, respectively, and the existence of microflora from underwater sediments in the bodies of $S.$ $broughtonii$ was analyzed. We screened the whole body of each sample and chose unique colonies, which exhibit alpha- and beta-hemolytic activity, for identification. The microflora in $S.$ $broughtonii$ was less variable than sediments, and restricted species were isolated. We identified 17 genera of 88 species and 16 genera of 64 species from the two bays, respectively. A major proportion was comprised of $Bacillus$ species, with the $Bacillus$ $cereus$ group being the most common species among the $Bacillus$ strains, while $Paenibacillus$, $Lynsilbacillus$, and $Vibrio$ species were the second most abundant species. At the genus level, there were no significant microbial differences between the two coastal regions. 64 species were isolated from rare site (Jinhae bay), but more species (88) with greater variety were isolated from the frequent site (Gangjin bay). Therefore, it was assumed that the cause of mass mortality lay in the difference in specie-level diversity, and conducting investigations on the diagnosis of pathogenic species by challenging tests using isolated unique species.

• Journal of Yeungnam Medical Science
• /
• v.1 no.1
• /
• pp.67-87
• /
• 1984

The earliest memories and dreams have been investigated in many aspects; biological, psychological, statistical, and psychotherapeutic, in psychiatric field. The approach methods to these psychic contents are innumerable according to the schools, the collector's attitudes to these materials, the collecting methods and the variable factors of the reporter. In this study the author attempted to compare the distribution of the aggression and dependency themes in these psychic contents among groups of different sexes and clinical diagnoses. In this purpose the author devised new scales, the Aggression and the Dependency Scales for the earliest memories and dreams which are composed of 12-theme classes, according to 3 aspects of the ego attitudes and 4 degrees of the intensity of drives. The scales were tested on a series of the earliest memories and dreams from 100 male medical students by two raters. The interrater reliabilities, measured by kappa method, were all significant at better than the .001 level. The author collected the reports of the earliest memories and dreams from 293 schizophrenics (161 males and 132 females) and 301 neurotics (164 males and 137 females) who were either outpatients or inpatients of 5 general hospitals and 2 private neurospychiatric clinics and from 310 controls (169 males and 141 females) who were either students, housewives or employees in Taegu area during the periods from March to August, 1980 and from April to August, 1983. The author compared the contents of the earliest memories and dreams from these 3 clinical groups on the newly devised scales and the results could be summarized as follows: In general, the contents of the earliest memories showed more differences among diagnostically different groups, while the contents of dreams showed more differences among sexually different groups. The dependency themes were more frequent than the aggression thems in all groups. The aggression themes were more frequent in dreams than in the earliest memories. Of the earliest memory themes, the distribution of the aggression themes was different among clinical groups, i.e., most frequent in schizophrenics, next in neurotics, and least in controls. The distribution of the dependency themes was in reverse order. Attitudes of being attacked were more frequent in schizophrenics. Observing attitudes of dependency need were more frequent in neurotics while gratifying attitudes were more frequent in controls. Highest degrees of aggression and delpendency were more frequent in neurotics. In the distribution of the dream themes, there were some differences among male and female schizophrenics. Aggression themes, especially active and the highest degree of aggression, were more frequent in male sclizophrenics, while dependency themes, especially frustrated themes, were more frequent in female schizophrenics. Among 3 clinical groups, observing attitudes of dependency need were more frequent in female groups, while gratifying attitudes were more frequent in male groups.