• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.1D
• /
• pp.107-117
• /
• 2008

Private financing is playing an increasing role in public infrastructure construction projects worldwide. However, private investors/operators are exposed to the financial risk of low profitability due to the inaccurate estimation of facility demand, operation income, maintenance costs, etc. From the operator's perspective, a sound and thorough financial feasibility study is required to establish the appropriate capital structure of a project. Operators tend to reduce the equity amount to minimize the level of risk exposure, while creditors persist to raise it, in an attempt to secure a sufficient level of financial involvement from the operators. Therefore, it is important for creditors and operators to reach an agreement for a balanced capital structure that synthetically considers both profitability and repayment capacity. This paper presents an optimal capital structure model for successful private infrastructure investment. This model finds the optimized point where the profitability is balanced with the repayment capacity, with the use of the concept of utility function and multi-objective GA (Generic Algorithm)-based optimization. A case study is presented to show the validity of the model and its verification. The research conclusions provide a proper capital structure for privately-financed infrastructure projects through a proposed multi-objective model.

• Journal of Family Resource Management and Policy Review
• /
• v.10 no.2
• /
• pp.87-105
• /
• 2006

The goal of this study is to analyze the complicated and diverse nature of the relationship between work and family life for the study paper instructors of whom are married women. The survey data for these analyses were from an in depth interview which was conducted with the 21 contingent female workers as study samples. They are the married women, who started to work or returned to work after an absence to raise a family. The results showed that in reality the contingent female worker faced worse working conditions than the full time female labour force, even if women were determined to be a study paper instructor to meet work and family demand. It was the contingent women worker with a short time work experience who were in the worst position tlo adjust their working arrangements to suit their family needs and were confronted with the greater inter-role friction as a vulnerable group. The study revealed that instrumental and emotional support of husband has a positive effect on maintaining job role and lessening role conflicts and stress of the women. The work/family relationship indicated its double side, conflict and support. The women simply could not afford to depend on the psychological support form family in the midst of the inferior employment conditions and the absence of social support. This strategy, however, was based on the family ideology and the patriarchal gender division of labor. It caused the overload, stress and poor health of women involving some risk to give up the work.

• Safety and Health at Work
• /
• v.4 no.1
• /
• pp.12-26
• /
• 2013

In concert with the development of new materials in the last decade, the need for toxicological studies of these materials has been increasing. These new materials include a group of rare earths (RE). The use of RE nanotechnology is being considered in some green applications, to increase their efficiency by using nano-sized RE compounds, and therefore hazard evaluation and risk assessment are highly recommended. This review was conducted through an extensive contemplation of the literatures in toxicology with in vitro and in vivo studies. Major aspects reviewed were the toxicological evaluations of these elements and metallic compounds at the molecular and cellular level, animal and human epidemiological studies and environmental and occupational health impacts on workers. We also discuss the future prospect of industries with appliances using RE together with the significance of preventive efforts for workers' health. To establish a safe and healthy working environment for RE industries, the use of biomarkers is increasing to provide sustainable measure, due to demand for information about the health risks from unfavorable exposures. Given the recent toxicological results on the exposure of cells, animals and workers to RE compounds, it is important to review the toxicological studies to improve the current understanding of the RE compounds in the field of occupational health. This will help to establish a sustainable, safe and healthy working environment for RE industries.

• Journal of Aerospace System Engineering
• /
• v.11 no.3
• /
• pp.31-38
• /
• 2017

As demand for best practices relative to flight test safety management operations and processes in the aviation industry grows, standards for such aspects of the industry in Korea should be examined. Therefore, in this paper, we conducted flight test operation processes and safety management program development studies based on documents related to flight tests of the Korean civil aviation KC-100, the military aircraft T-50, the FAA (Federal Aviation Administration), and CAAC (Civil Aviation Administration of China) for performance validation, test evaluation and safety certification for aircraft under development and remodeling. In addition, we introduced and analyzed best practices of the FTSC (Flight Test Safety Committee) applicable to aircraft flight test processes.

• Journal of the Speleological Society of Korea
• /
• no.64
• /
• pp.27-36
• /
• 2004

Caves have the values of learning sites and tourism resources. But show caves are at risk of being ravaged, destroyed, and Polluted. The Purpose of this study is to analyse the management condition and the problems of the show caves, and to suggest the alternative improvement for the cave management. The research of the Cultual Properties Administration revealed many Problems including the management system, safety diagnosis, the demand for comprehensive academic research and so on. An analyzing of the questionnaire about cave manager demanded to reform working conditions, tourist education, an amendment of the Cultural Properties Protection Act, expert education for cave manager. In conclusion, It is necessary that construct the mutual cooperation system of an administrative organization, cave manager and tourist, and the Cave Management information System to manage database of cave environment.

• Journal of Korea Water Resources Association
• /
• v.43 no.1
• /
• pp.95-104
• /
• 2010

The tap water supply in Korea mainly depends on the surface water. However, the advanced water purification process becomes a necessity due to the deterioration of surface water quality and the risk of accidental spill. High cost of water treatment and public concerns make the decision makers turn to riverbank filtration as an alternative to the surface water. Riverbank filtration has been employed for water supply in many developed countries for more than 150 years. In Korea, riverbank filtration has drawn attention since 1990s as a supply source having potential to stably meet the ever-increasing water demand. Some cities located in the Nakdong River Basin are currently supplying water through riverbank filtration. This work studies the site suitability analysis for riverbank filtration using game theory. Theory of games, which is a branch of applied mathematics used in social sciences (most notably economics), biology, engineering and computer science, was applied to candidate locations for the selection of riverbank filtration site. We proposed a policy game model as a new method adopting a probabilistic approach. The model developed turned out to be an effective tool for site selection.

• International Commerce and Information Review
• /
• v.14 no.3
• /
• pp.31-47
• /
• 2012

The Eurozone was launched to set a goal on using the single currency perfectly in 1999. Using the Euro could get rid of exchange cost and cost of Foreign exchange risk management which was approximately 1% of each member's GDP. It was possible that members has maintained a stable level of inflation and stimulate investment and employment with low interest rate. In addition, they could lead to economic growth and investment as well as increase the Euro demand in financial market. Especially, members has used the Euro as the method of payment on trade each other so that the volume of trade among the Eurozone members has increased continuously which was called "the effect of single market." This paper analyzes the correlation between using the Euro and members' export/import by using random effect estimation and fixed effect estimation. As a result, Eurozone members can get export decreasing effect of 4.68% and import increasing effect of 10.5% respectively on average by using the Euro.

• Journal of the Korea Furniture Society
• /
• v.26 no.1
• /
• pp.61-70
• /
• 2015

There is an increasing trend each year in the number of subway users due to increase in the traffic volume. As the number of train service has risen, the subway drivers are given heavy work and from the same, are put at risk of mental health deterioration due to stress. As this is directly connected to safety, there is an urgent need for improvement of the situation. Therefore, as a way to appropriately relieve such stress, resting space where mental and physical energy can be recharged is necessary. Thus, this research conducted a survey of demand with subway drivers as subjects in order to provide resting space that can offer healthy rest and increase work effectiveness. 50 subway drivers were the subjects of this survey. As a result of analyzing the contents of the survey, environmental satisfaction was shown to be the lowest compared to psychological and morphological satisfaction. In the case of sleeping room, they wanted more comfortable and individual space. And the waiting room had the highest rate of usage frequency. The storage space was where the subway drivers showed the strongest attachment and was shown to be the only personal space. Most were shown to be satisfied with the outdoor space, but it had the lowest usage frequency. In addition, it is nessasery customized storage cabinet designed for subway drivers should be produced, which can effectively arrange the limited space. I hope that these direction of improvement can increase the healthy rest and work effectiveness of the locomotive engineers as it is directly being connected to the health and safety of the citizens.

• Journal of Korean Neurosurgical Society
• /
• v.48 no.2
• /
• pp.105-108
• /
• 2010

Objective : Some neurosurgeons intentionally ligate the branches of the superficial temporal artery (STA) that are not used in standard STA-to-middle cerebral artery (MCA) anastomosis for the purpose of improving the flow rate in the bypass graft. We investigated changes in bypass flow during temporary occlusion of such unused branches of the STA. Methods : Bypass blood flow was measured by a quantitative microvascular ultrasonic flow probe before and after temporary occlusion of branches of the STA that were not used for anastomosis. We performed measurements on twelve subjects and statistically assessed changes in flow. We also examined all the patients with digital subtraction angiography in order to observe any post-operative changes in STA diameter. Results : Initial STA flow ranged from 15 mL/min to 85 mL/min, and the flow did not change significantly during occlusion as compared with preocclusion flow. The occlusion time was extended by 30 minutes in all cases, but this did not contribute to any significant flow change. Conclusion : The amount of bypass flow in the STA seems to be influenced not by donor vessel status but by recipient vessel demand. Ligation of the unused STA branch after completion of anastomosis does not contribute to improvement in bypass flow immediately after surgery, and furthermore, carries some risk of skin necrosis. It is better to leave the unused branch of the STA intact for use in secondary operation and to prevent donor vessel occlusion.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.48 no.4
• /
• pp.542-554
• /
• 2015

Grain size, the content of ignition loss (IL), and the concentrations of chemical oxygen demand (COD), acid volatile sulfide (AVS), and trace metals (Fe, Mn, Cu, Pb, Zn, Cd, Cr, As, and Hg) in surface sediments from the Taehwa River estuary, Ulsan, were measured to evaluate pollution levels and potential ecological risks of organic matter and trace metals in estuarine sediment. The mean grain size (Mz) of sediments in the study region ranged from $-0.8-7.7{\varphi}$ (mean $2.8{\pm}2.4{\varphi}$). Surface sediments in the upstream region of the Taehwa River were mainly composed of coarse sediments compared to the downstream region. The concentrations of IL, COD, AVS and trace metals in the sediment were much higher at downstream sites of Myeongchon Bridge in the vicinity of industrial complexes than at upstream sites of those in the vicinity of the residential areas due to the anthropogenic input of organic matter and trace metals by industrial activities. On the basis of several geochemical assessment techniques [sediment quality guidelines (SQGs), enrichment factor (EF), geoaccumulation index ($I_{geo}$), pollution load index (PLI) and ecological risk index (ERI)], the surfaces sediments in the study region are not highly polluted for trace metals, except for As. However, the higher concentrations in downstream study regions of the Taehwa River could impact benthic organisms including shellfish (i.e. Manila clam) in sediments.