• Journal of Distribution Research
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• v.10 no.1
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• pp.59-84
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• 2005

Most of previous studies have proposed representative product categories which are likely to be sold on the on-line based only on the on-line benefits and risks. However, on-line shopping can be perceived another form of distribution channels from the perspectives of consumers. Therefore, in order to identify product categories which have a great potential to be sold on on-line stores, it is necessary to consider the perception and behavior at off-line shopping contexts as well as on on-line shopping circumstances. In this paper, we investigate the consumers' perception and behavior under both on-line and off-line shopping situations and classify them into several groups based on their perceptual and behavioral characteristics. Based on this classification, we empirically examine the product categories selling well on the on-line shopping. The empirical results show that there exist some patterns between distribution channels (on-line and off-line) and product categories. In addition, there are some differences among consumers regarding the perceptions and behaviors at on-line and off-line situations. Consumers who have high preference for on-line shopping tend to buy much wider product categories from on-line.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.4
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• pp.407-414
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• 2010

The fairway within the area of Yul-do and Songdo located near the Myeongnyang-sudo approaches south of Mokpo harbor is well guided by traffic separation scheme and other navigational aids. However, that part of the waterways where Yul-do is located sits at the cross-roads of marine traffic and is subjected to some potential risks in the voyage navigation: the effect of climatic phenomenon, the disregard of most ships in using the western sector of the fairway creating a congestion in the eastern sector, and lastly, the disadvantageous erect of the location and height of Yul-do island that hinders good lookout. This study investigates the environmental conditions that prevailed in the area in the span of 5-year period and the marine traffic situation taken from the data within the 72-hour period The navigational hazards and marine casualties are also be presented. The results are analyzed and are made the basis of a proposal for an improved separation of traffic. Thereafter, an evaluation is carried out by using the components of marine traffic flow simulation and ES modeling index. It is evaluated through simulation by the use of full-mission ship handling simulator.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.373-378
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• 2003

Korea's overseas construction industry has been rather depressed by the weakened profitability as well as the sharp decrease of the market shares due to the lack of international competitiveness and the declined international market following the outbreak of Iraq war. There exist a lot of various risks in performing the overseas construction, and especially EPC projects, which entail complicated process from different parts, also require a sophisticated procurement and management skill. Subsequently, to survive in the competitive international market, we need to establish strategies to select potentially profitable projects at the initial stage of bidding process and to mitigate the high degree of risk exposures through contract negotiation and its adjustment. This research provides the profitability evaluation bases, with which overseas construction participants can forecast and analyze the risk more systematically, by eliciting profit-influencing factors from real overseas construction projects and structuring their cause-and-effect relationships. The profitability causal hierarchy structure describes the profitability factors' hierarchy in details and their interrelationships. It also enables us to find out critical factors directly related to profitability aggravation through a qualitative analysis. Ultimately, with this hierarchy structure as the base, the research will suggest how to develop the quantitative profitability forecasting model.

• Journal of Preventive Medicine and Public Health
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• v.41 no.5
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• pp.307-314
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• 2008

Objectives : We conducted an epidemiologic survey to evaluate the effect of the aircraft noise exposure on the health of the residents near the military airbases in Pyeongtaek City. Methods : The evaluation of environmental noise level, questionnaire survey, and health examination were performed for 917 residents. The study population consisted of four groups: subjects who lived in the village close to the fighter airbase (high exposure), subjects who lived along the course of fighters (intermediate exposure), and subjects near a helicopter airbase, and the control group. Results : The prevalence of the aircraft noise related accident and irritable bowel syndrome in the exposure groups were higher than that of the control group. The risks of noise induced hearing loss, hypertension and diabetes mellitus were higher in the exposed groups than in the control group. The prevalence of anxiety disorder and primary insomnia were higher in the exposed groups than in the control group. Prevalence odd ratios of the risk for primary insomnia after adjusting age, sex, agricultural noise, and occupation were 4.03 [95% confidence interval (95% Cl) 1.56-10.47] for the subject near the helicopter airbase, 1.23 (95% Cl 0.40-3.76) for those intermediately exposed to fighter noise, and 4.99 (95% Cl 2.14-11.64) for those highly exposed to fighter noise. Conclusions : The results of the present study suggest that the aircraft noise may have adverse effects on hearing function, cardiovascular health and mental health. Therefore, it seems to be needed to take proper measures including the control of the aircraft noise and the management of the exposed people's health.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.5
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• pp.981-986
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• 2020

The Internet of Things refers to a space-of-things connection network configured to allow things with built-in sensors and communication functions to interact with people and other things, regardless of the restriction of place or time.IoT is a network developed for the purpose of services for human convenience, but the scope of its use is expanding across industries such as power transmission, energy management, and factory automation. However, the communication protocol of IoT, MQTT, is a lightweight message transmission protocol based on the push technology and has a security vulnerability, and this suggests that there are risks such as personal information infringement or industrial information leakage. To solve this problem, we designed a synchronous MQTT security channel that creates a secure channel by using the characteristic that different chaotic dynamical systems are synchronized with arbitrary values in the lightweight message transmission MQTT protocol. The communication channel we designed is a method of transmitting information to the noise channel by using characteristics such as random number similarity of chaotic signals, sensitivity to initial value, and reproducibility of signals. The encryption method synchronized with the proposed key value is a method optimized for the lightweight message transmission protocol, and if applied to the MQTT of IoT, it is believed to be effective in creating a secure channel.

• Journal of Nutrition and Health
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• v.43 no.5
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• pp.463-474
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• 2010

The nutrient intake and association between dish group intake and blood glucose and serum lipid level (TG, cholesterol, LDL and HDL) was analyzed among 3 groups: 452 subjects in normal blood glucose group (NG: fasting blood glucose < 100 mg/dL and 2 hours postprandial blood glucose < 140 mg/dL), 258 subjects in impaired fasting glucose group (IFG: fasting blood glucose 100~125 mg/dL and 2 hours postprandial blood glucose ${\geq}$ 140 mg/dL) and 101 subjects in diabetic group (DG: fasting blood glucose $\geq$ 126 mg/dL and 2 hours postprandial blood glucose ${\geq}$ 140 mg/dL). The data were obtained from the 2005 National Health and Nutrition Survey of Korea. The 811 subjects were adults aged 40~64 without dietary treatment. In nutrients intake, IFG was the highest and DG the lowest in both quantity and quality. DG, especially, had the lowest intake in carbohydrates, fiber, proteins, Ca, P, K, vitamins B1 and C, and consumed the highest amount of alcohol. In macronutrients distribution ratio, the DG diet showed a lower energy intake from carbohydrates but higher from fat than the NG diet, while IFG showed a higher energy intake from carbohydrates and lower intake from fat in supper out of 3 meals and snacks. IFG preferred salt-fermented foods and DG preferred soups, braised foods and kimchi compared to other groups. NG preferred multi-grain cooked rice and both IFG and DG preferred plain white cooked rice. Regarding the association between dish group intake and blood glucose, cooked rice, soups, salt-fermented foods and kimchi were significantly related to blood glucose. In blood lipids, steamed-foods, beverages and fruits were inversely related to the risk of developing type 2 diabetes, whereas cooked rice, stews, saltfer-mented foods, seasoned-fermented foods and seasoned vegetables were directly proportional to the risk of developing type 2 diabetes and related diseases. Therefore, it is beneficial to avoid rich, salty and fatty foods and heavy alcohol consumption for controlling blood glucose and blood lipids, while steamed foods, foods rich in fiber (like multigrain rice) as a staple, and fruits and teas are recommended for preventing or managing type 2 diabetes risks.

• Journal of Navigation and Port Research
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• v.39 no.3
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• pp.199-207
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• 2015

In ports of Korea, the marine traffic flow is congested due to a large number of vessels coming in and going out. In order to improve the safety and efficiency of these vessels, South Korea is operating with a Vessel Traffic Service System, which is monitoring its waters for 24 hours. However despite these efforts of the VTS (Vessel Traffic Service) officers, collisions are occurring continuously, the risk situation is analyzed that occurs once in about 20 minutes, the risk may be greater. It investigated to reduce these accidents by providing a safety standard for collision danger in a timely manner. Thus, this study has developed a risk prediction module to predict risk in advance. This module can avoid collision risk to adjust the speed and course of ship using a risk evaluation model based on ship operator's risk perspective. Using this module, the ship operators and VTS officers can easily be identified risks in complex traffic situations, so they can take an appropriate action against danger in near future including course and speed change. To verify the effectiveness of this module, this paper predicted the risk of each encounter situation and confirmed to be capable of identifying a risk changes in specific course and speed changes at Busan coastal water.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.9
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• pp.667-674
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• 2014

A ship's propulsion shafting system is subjected to varying magnitudes of intermittent loadings that pose great risks such as failure. Consequently, the dynamic characteristic of a propulsion shafting system must be designed to withstand the resonance that occurs during operation. This resonance results from hydrodynamic interaction between the propeller and fluid. For ice-class vessels, this interaction takes place between the propeller and ice. Producing load- and resonance-induced stresses, the propeller-ice interaction is the primary source of excitation, making it a major focus in the design requirements of propulsion shafting systems. This paper examines the transient torsional vibration response of the propulsion shafting system of an ice-class research vessel. The propulsion train is composed of an electric motor, flexible coupling, spherical gears, and a propeller configuration. In this paper, the theoretical analysis of transient torsional vibration and propeller-ice interaction loading is first discussed, followed by an explanation of the actual transient torsional vibration measurements. Measurement data for the analysis were compared with an applied estimation factor for the propulsion shafting design torque limit, and they were evaluated using an existing international standard. Addressing the transient torsional vibration of a propulsion shafting system with an electric motor, this paper also illustrates the influence of flexible coupling stiffness design on resulting resonance. Lastly, the paper concludes with a proposal to further study the existence of negative torque on a gear train and its overall effect on propulsion shafting systems.

• Journal of the Korean Society of School Health
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• v.23 no.2
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• pp.246-255
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• 2010

Purpose: This study is based on an experimental research program designed to evaluate the before and after states of a control group that undertook a series of smoking prevention education sessions. Methods: The research was undertaken between June 2 and July 22, 2008. Students from two public elementary schools in Uiwang City took part in the study. 76 students from one of the schools (School 'W') were designated as the experimental group and 89 students from the other school (School 'O') were allotted to the control group. During the research period, the experimental group held 10, 40 minute discussions on the subject of smoking prevention. The control group had no such sessions and no information was given. The data was collected in 3 stages, firstly after initial study preparation, secondly after five sessions and thirdly after ten sessions. The data was analysed using the SPSS/WIN 12.0 program. Results: First, there was a presumption that the experiment group would have a greater knowledge about the effects of smoking than the control group. This was supported by the data analysis results (F=41.79, p =.000). Second it was presumed that the experiment group would have a more informed attitude to smoking than the control group. This was supported by the data analysis results (F=6.917, p =.009). Third, there was the presumption that the experiment group would have a greater knowledge of the effects of smoking after ten sessions than they would five sessions. This was supported by the data analysis results (F=56.911, p =.000, Scheffe=3rd> 2nd>1st). Fourth, the presumption held that the experimental group would have a more informed attitude to the effects of smoking after ten sessions than they did five. This was supported by the data analysis results (F=14.607, p =000, Scheffe=3rd>2nd>1st). Conclusion: The results appear to show that the elementary school students who participated in the smoking prevention sessions had an increased knowledge of the risks and had also formed a more negative attitude towards smoking. On the basis of the findings of this study, I would suggest that there are benefits in developing learner-centered smoking prevention programs and other related media. Also, smoking prevention discussions should be included in the regular curricula relating to health education.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.1
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• pp.41-47
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• 2014

Agricultural soils surrounding mine areas in South Korea are often contaminated with multiple metals such as Cd, Pb and Zn. It poses potential risks to plants, soil organisms, groundwater, and eventually human health. The aim of this study was to examine the changes in phytoavailability of Cd, Cu, Pb and Zn after application with calcined eggshell (CES; 0, 1, 3, and 5% W/W) in an agricultural soil contaminated by mine tailings. The contents of Cd, Cu, Pb and Zn in soils were 8.79, 65.4, 1602, and $692mgkg^{-1}$ (aqua regia dissolution), respectively. The experiments were conducted with lettuce (Lactuca sativa L. var. longifolia) grown under greenhouse conditions during a 30-d period. $NH_4NO_3$ solution was used to examine the mobile fraction of these metals in soil. The application of CES dramatically increased soil pH and inorganic carbon content in soil due to CaO and $CaCO_3$ of CES. The increased soil pH decreased the mobile fraction of Cd, Pb, Zn: from 3.49 to < $0.01mgkg^{-1}$ for Cd, from 79.4 to $1.75mgkg^{-1}$ for Pb, and from 29.6 to $1.13mgkg^{-1}$ for Zn with increasing treatment of CES from 0 to 5%. In contrast, the mobile fraction of Cu was increased from 0.05 to $3.08mgkg^{-1}$, probably due to the formation of soluble $CuCO_3{^0}$ and Cu-organic complex. This changes in the mobile fraction resulted in a diminished uptake of Cd, Pb and Zn by lettuce and an increased uptake of Cu: from 4.19 to < $0.001mgkg^{-1}$ dry weight (DW) for Cd, from 0.78 to < $0.001mgkg^{-1}$ DW for Pb, and from 133 to $50.0mgkg^{-1}$ DW for Zn and conversely, from 3.79 up to $8.21kg^{-1}$ DW for Cu. The increased contents of Cu in lettuce shoots did not exceed the toxic level of $>25mgkg^{-1}$ DW. The mobile contents of these metals in soils showed a strong relationship with their contents in plant roots and shoots. These results showed that CES effectively reduced the phytoavailability of Cd, Pb, and Zn to lettuce but elevated that of Cu in consequence of the changed binding forms of Cd, Cu, Pb, and Zn in soils. Based on these conclusions, CES can be used as an effective immobilization agent for Cd, Pb and Zn in contaminated soils. However, the CES should be applied in restricted doses due to too high increased pH in soils.