• Journal of Korean Neurosurgical Society
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• 제40권2호
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• pp.69-73
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• 2006

Objective : The optimal surgical treatment for symptomatic middle cranial fossa arachnoid cysts is controversial. Therapeutic options include endoscopic fenestration, excision, cyst shunting, and craniotomy for fenestration of basal cistern. We reviewed the results of surgically treated middle cranial fossa arachnoid cysts. Methods : We performed a retrospective study in 18 cases of middle cranial fossa arachnoid cysts who had been treated with microsurgical fenestration between 1995 to 2003. The analysis was based on the results of the patients' age, sex distribution, developed area, clinical symptoms, treatment method, and complications. Results : Eighteen surgical treated middle cranial fossa arachnoid cysts patients were evaluated. The age range of cyst development was between 2 years and 44 years with the average of 16.4 years. The follow-up periods averaged 31.48 months. There were 15 male and 3 female patients, with significantly more cyst development in males than females. The most common clinical symptom was headache, followed by seizure. In the entire series, 77.8% of patients demonstrated a decrease in cyst size In serial imaging studies. Of them, 67.3% demonstrated a complete cyst effacement. Overall, 100% of patients with Grade I cysts, 81.8% of patients with Grade II cysts, 60% of patients with Grade III cysts exhibited evidence of decrease in cyst size during long-term monitoring. Complications included headache, meningitis, and hydrocephalus. Conclusion : Patients who were treated with microsurgical fenestration showed good outcome with acceptable complications. We concluded that microsurgical fenestration is a safe and effective surgical method for middle cranial fossa arachnoid cysts.

• The Journal of Asian Finance, Economics and Business
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• 제7권8호
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• pp.259-268
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• 2020

The study investigates the association between CEO education and firm performance with a sample of 85 nonfinancial firms listed on the Saudi stock exchange during 2018 applying ordinary least squares method. CEO education is defined by three variables, the level of education, if the degree-granting institution is domestic or foreign, and if the highest degree is in management or other fields of study. Financial performance is measured by return on assets and return on equity. Firm size, age, liquidity and growth are introduced as control variables. The study shows that 58 CEOs of the firms studied are graduates, 38 have obtained their degree from a domestic institution and 44 have a management degree. Graduate CEOs are found to enhance performance. Graduating from a domestic institution influences performance positively. Management degree of CEO does not seem to impact performance. Firm size, liquidity and growth are positively associated with performance. Firm age does not explain performance differences of firms. Results are robust to performance measures. The findings of the study suggest that firms can benefit from a CEO hiring policy that emphasizes on the minimum qualification set as graduation or higher, education from a domestic institution and no undue weight on management qualification.

• The Journal of Asian Finance, Economics and Business
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• 제8권5호
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• pp.287-292
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• 2021

The article analyzes the impact of capital structure on the firm value of chemical companies listed on the stock market of Vietnam. Data was collected from the financial statements of 23 chemical firms listed on the Vietnam stock market from 2012 to 2019. Quantitative research method with regression model according to OLS, FEM, REM method is used; FGLS method is used to overcome the model's defects. In this research, firm value (Tobin's Q) is a dependent variable. Capital structure (DA), Return on assets (ROA), Asset turnover (AT), fixed assets (TANG), Solvency (CR), Firm size (SZ), Firm Age (AGE), and revenue growth rate (GR) are independent variables in the study. The analysis results show that the capital structure of firms in the chemical industry listed on the Vietnam stock market has an inverse correlation with firm value. Besides, firms with greater asset turnover, business size, and number of years of operation have lower firm value. This article helps corporate executives improve corporate value by adjusting their capital structure properly. Chemical firms adjusted their capital structure in the direction of gradually decreasing the debt ratio and gradually increasing equity. Firms use high debt, which has the effect of reducing the firm value of firms in the chemical industry.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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• pp.675-682
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• 2021

The study analyzes the demand for residential space in the Untact Era. Residential space comprises six categories: the most necessary dedicated space (DS), most preferred south-facing space (SFS), largest space (LS), most necessary shared space (SS), most necessary infra-space (IS), and others. Results indicated the following: 1) All respondents had the highest preference for relaxing spaces except DS. 2) Differences were found between DS, SFS, and LS by age and SS; IS by residential area; and DS, SS, and IS by household size. 3) People aged 60+ preferred a living room while people aged 40-59 preferred a larger kitchen. Seoul citizens preferred gardens or parks in the complex or neighboring forests whereas local citizens preferred shared offices and medical centers. Households of three or more persons preferred a park/forest and two-person households preferred a honbap restaurant. The implications for housing policy are as follows. 1) Nature-friendly spaces are needed to alleviate a sense of isolation. 2) Changing demand for residential space should be reflected in housing policies. 3) The government's housing supply policy with the same residential space and structure must be changed to provide various residential spaces according to age, residential area, and household size.

• 대한인간공학회지
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• 제18권2호
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• pp.11-24
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• 1999

The purpose of this study was to obtain the basic data for sound wear design. The objects' of this study were 331 women's university students. The eight items were the shoulder length, shoulder slope, height, weight, chest girth, neck girth, back length, and back shoulder width. The shoulder length and slopes were measured, compared with the right, the left, and other items. The results were as follows; The difference between the right and left shoulder length did not nearly appear. The mean of the right shoulder slopes was $21.3^{\circ}$, and that of the left was $21.9^{\circ}$. According to increase of the age, the right and left shoulder slope tends to be higher. The maximum distribution was $20.7^{\circ}$. According to increase of the age, the maximum distribution tends to be higher. The left compared with the right shoulder length, the right shoulder length of 90.3% objects' was longer than that of the left. The right and left shoulder length of 4.2% objects' were same. The left shoulder length of 5.4% objects' was longer than that of the right. The left compared with the right shoulder slopes, the right shoulder slopes of 12.7% objects' were higher than those of the left. The both size of 20.5% objects' were equal. The left slopes of 66.8% objects' was higher than those of the right.

• 유통과학연구
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• 제20권12호
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• pp.13-22
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• 2022

Purpose: The paper contributes to the existing literature on Vietnamese corporate governance and firm performance with a focus on listed family firms and the use of a more suitable econometric framework to analyze firm performance. The study investigates how family firm performance is affected by corporate governance under the standpoint of stewardship theory in Vietnam. Research design, data and methodology: With the use of different measures for firm performance (Tobin's Q, ROA, and ROE), regression models were estimated using Generalized Least Square (GLS) method on a panel data of a total of 113 listed companies during the five-year period from 2015 to 2019. Results: We found that family ownership as the main characteristic of the stewardship theory affects family firms positively. In addition, several other characteristics in corporate governance as board composition (board independence, board audits, and board committees), CEO (age and tenure) and firm characteristics (size, age, expansion, and annual sales) showed significant impacts on firm performance. Our findings also suggest that family firm performance can be either positively or negatively affected based on the characteristics of corporate governance. The findings can help companies evaluate the significance of corporate governance through deciding board structure and the selection of CEOs to match family firm characteristics. It also gives insights for investors, rating agencies, and policymakers for relevant purposes.

• The Korean Journal of Ecology
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• 제28권5호
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• pp.327-333
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• 2005

시화호 내 형성된 위성류 자연 군락의 개체군 특성을 밝히기 위해 매목의 크기, 공간분포 및 뿌리의 생장형태를 국내 최초로 조사하였다. 위성류 군락은 남북으로 약 350 m, 동서로 270 m 범위에 형성되어 있었다. 동일한 뿌리로부터 발생한 줄기는 평균 1.9개이었는데 지면에서 갈라진 줄기를 각각의 개체로 간주하였을 때(줄기 기준) 살아있는 개체는 총 1,398개체이었으며 고사한 것은 114개체로 총 1,512개체가 조사되었다. 지면으로부터 20 cm높이에서의 평균둘레는 $5.9{\pm}3.2$ cm, 평균높이는 $159{\pm}51$ cm이었다. 개체의 둘레 크기를 10계급으로 구분한 결과 두번째로 작은 계급의 개체수 가장 많았으며 크기가 증가할수록 개체수가 감소하였다. 그러나 높이 크기를 10계급으로 구분한 결과는 정규분포에 가까운 형태를 나타냈다. 고사한 개체는 둘레 크기에는 작은 계급에 속하였으나 높이의 크기에서는 상위 2계급만 제외하고 전 계급에 분포하였다. 동일한 지하부를 갖고 있는 개체를 하나로 간주하였을 경우(뿌리 기준) 20 cm 높이에 서의 면적을 10계급으로 구분한 결과 가장 작은 크기의 개체가 대부분을 차지하였고(83.8%), 크기가 증가할수록 개체수가 현저히 감소하였다. 위성류 매목은 군락의 중심에 집중분포를 하였으며 상대적으로 남북 방향이 동서방향보다 더욱 심한 집중분포의 경향을 보였다. 가장 큰 매목의 수령은 8년이었다. 위성류 뿌리의 생장형태는 크게 두 가지인데 하나는 지표면 근처에서 수평 방향으로, 다른 하나는 수직 방향으로 생장하고 있었다.

• 한국농공학회논문집
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• 제59권6호
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• pp.61-71
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• 2017

The tracer gas method has an advantage that can estimate total and local ventilation rate by tracing air flow. However, the field measurement using tracer gas has disadvantages such as danger, inefficiency, and high cost. Therefore, the aim of this study was to evaluate ventilation rate in pig house by using the thermal distribution data rather than tracer gas. Especially, LMA (Local Mean Age), which is an index based on the age of air theory, was used to evaluate the ventilation rate in pig house. Firstly, the field experiment was conducted to measure micro-climate inside pig house, such as the air temperature, $CO_2$ concentration and wind velocity. And then, LMA was calculated based on the decay of $CO_2$ concentration and air temperature, respectively. This study compared between LMA determined by $CO_2$ concentration and air temperature; the average error and root mean square error were 3.76 s and 5.34 s. From these results, it was determined that thermal distribution data could be used for estimation of LMA. Finally, CFD (Computational fluid dynamic) model was validated using LMA and wind velocity. The mesh size was designed to be 0.1 m based on the grid independence test, and the Standard $k-{\omega}$ model was eventually chosen as the proper turbulence model. The developed CFD model was highly appropriate for evaluating the ventilation rate in pig house.

• 콘크리트학회논문집
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• 제16권6호
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• pp.875-881
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• 2004

The quality of recycled aggregate is affected by original concrete strength and the manufacturing process of recycled aggregates. In this study, the porosity of old and new mortar, and the compressive strength of concrete were investigated to examine the influence of recycled aggregate on the concrete. Six kinds of recycled coarse aggregates were produced from concrete blocks of differing strength levels (A:60. 1MPa, B:41.7MPa, C:25.5MPa). Original concrete strength and the bond mortar of recycled aggregate influences the pore structures of both old and new mortar. The pore size distribution of old mortar was found to be greatly affected by age, and the reduction of the porosity of bond mortar on low strength recycled aggregate increased at a greater rate than that of bond mortar on high strength recycled aggregate. The pore size distribution of new mortar in recycled aggregate concrete changed in comparison with that of new mortar in virgin aggregate concrete. The total porosity of new mortar using B level recycled aggregates was smaller than that of new mortar with A, and C level recycled aggregates. Moreover, the compressive strength of recycled aggregate concrete was found to have been affected by original concrete strength. The compressive strength of concrete only changed slightly in the porosity of new mortar over $15\%$, but increased rapidly in the porosity of new mortar fewer than $15\%$.

• 한국어류학회지
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• 제29권3호
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• pp.197-204
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• 2017

강원도 고성군 북천에서 종개 Orthrias toni의 생활사를 조사하여 생물학적 특징을 밝혔다. 성장은 수온이 $10^{\circ}C$ 이상 되는 4월부터 10월까지 빨랐으나 수온이 $10^{\circ}C$ 이하인 11월부터 이듬해 3월까지는 거의 멈추었다. 연령은 전장빈도분포도로 볼 때 산란기인 5월을 기준으로 전장 60~81 mm는 만 1년생, 82~99 mm는 만 2년생, 100~119 mm는 만 3년생, 120~140 mm는 만 4년생 이상으로 추정되었다. 암컷과 수컷의 연령별 전장 범위는 거의 동일하였고, 성비(♂/♀)는 0.73으로 암컷이 많았다. 산란기는 생식소성숙도(GSI)로 추정한 결과 5월이었으며, 이때의 수온은 $14{\sim}17^{\circ}C$였다. 생식소는 모든 연령이 성숙하였고, 연령이 높아지면서 포란수는 급격히 증가하였으며, 평균 $4,460{\pm}3,302$개였다. 성숙란의 크기는 연령과 상관없이 직경 $0.87{\pm}0.03mm$로 비슷하였다.