• KIPS Transactions on Computer and Communication Systems
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• v.2 no.1
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• pp.15-26
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• 2013

IP-based Wireless Sensor Networks (IP-WSNs) are gaining importance for their broad range of applications in health-care, home automation, environmental monitoring, industrial control, vehicle telematics and agricultural monitoring. In all these applications, mobility in the sensor network with special attention to energy efficiency is a major issue to be addressed. Because of the energy inefficiency of networks-based mobility management protocols can be supported in IP-WSN. In this paper we propose a network based mobility supported IP-WSN protocol called Multicasting-based inter-Domain Mobility Management Scheme in Sensor-based Fast Proxy Mobile IPv6 Networks (mSFP). Based on [8,20], We present its network architecture and evaluate its performance by considering the signaling and mobility cost. Our analysis shows that the proposed scheme reduces the signaling cost, total cost, and mobility cost. With respect to the number of IP-WSN nodes, the proposed scheme reduces the signaling cost by 7% and the total cost by 3%. With respect to the number of hops, the proposed scheme reduces the signaling cost by 6.9%, the total cost by 2.5%, and the mobility cost by 1.5%. With respect to the number of IP-WSN nodes, the proposed scheme reduces the mobility cost by 1.6%.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.4
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• pp.32-40
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• 2008

In this study, we monitor ice cap using calculated NDSI from September to December in 2001, 2003, 2006, 2007 and snow cover area in 2007 decrease by compare with 2001. Global warming is one of the most important issue in this world. Because global-warming is the reason of various meteorological disasters and extreme weather events in these days and snow and glaciers showed that global warming effect most easily. Snow and glaciers play an important role in Earth cooling system because of their high reflectance. The present study has been carried out monitoring ice cap in Himalayas, using MODIS(Moderate Resolution Imaging Spectroradiometer)data. Indicator to monitoring ice cap, NDSI(Normalized Differenced Snow Index) was used in this study. The NDSI is a spectral band ratio that takes advantage of the spectral differences of snow in visible and short-wave infrared domain to detect snow cover area versus non-snow cover area in a scene. This study is quantitative evaluation about effect of global warming for icecap.

• Journal of Energy Engineering
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• v.24 no.2
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• pp.129-143
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• 2015

Increasing concerns on climate change and energy security accelerated policies to reduce green-house gas emission, especially from the transportation sector. Electric vehicle (EV) has been on the spotlight to deal with such environmental issue and V2G (Vehicle-to-Grid) technology began to draw attentions as an alternative to reduce ownership costs while contributing to an efficient and decentralized power grid. This study conducts a scenario analysis on total cost of ownership of EV under V2G scheme and compare with non-V2G EV and Internal Combustion Engine (ICE) vehicle. As result, V2G service is expected to provide an annual average profit of $210 to EV users willing to reverse flow its residual power in the battery. The profit from V2G service leaves a margin of $4,530 over operational lifetime, compared with $2,420 cost of charge for non-V2G EV. In summary, total cost of ownership of V2G-capable EV was 6.2% less than non-V2G EV and 10.2% higher than ICE vehicle. The results confirm a comparative economic advantage of operating EV under V2G scheme. Increased number of EVs with V2G service has shown to provide positive effects to power industry for valley filling in load distribution, thus, favorably increasing the overall economic feasibility.

• Journal of the Korean Society of Radiology
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• v.14 no.4
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• pp.385-390
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• 2020

In the present, external environmental factors affect human health. In particular, the most important issue is fine dust in these days. Because fine dust is inhaled through the human respiratory system is known to be harmful to health. Tunnels for cars and people can also be easily seen around us. This study, the amount of scattering radiation was measured for walkable tunnels about dust. For the measurement method, dust and radiation dose in the tunnel were measured on good weather (fine dust level: 0 ~ 30 ㎍/㎥) and normal day (fine dust level: 0 ~ 80 ㎍/㎥). The measurement resulted in an increase of 10~20 % of dust in the center of the tunnel on a good weather day and an increase of 20~30 % of dust in the center of the tunnel on normal weather. On the other hand, the results of tunnel measurement of radiation dose increased by 10~20 % at the center of the tunnel non-depending on the weather. As a result, pedestrians should pay attention to scattering dust and scattered radiation while moving through the tunnel. Therefore, it is recommended to wear a filter mask of PM2.5 or less during frequent tunnel walking.

• Journal of the Korean Wood Science and Technology
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• v.39 no.3
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• pp.221-229
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• 2011

Due to the increase of oil price and the environmental issue such as the emission of volatile organic compounds, the necessity for developing alternative resins of petroleum-based adhesive resins, which have extensively been used for the manufacture of wood-based products, has been speculation since the early 1990. In our study, rapeseed flour (RSF), which is the by-product of bio-diesel produced from rapeseed, were hydrolyzed by enzymes. As a crosslinking agents of the RSF hydrolyzates, phenol-formaldehyde prepolymers (PF) were prepared. The RSF hydrolyzates and PF were mixed to complete the formulation of RSF-based adhesive resins, and the resins were applied to make the laminated veneer lumber (LVL). The physical and mechanical properties of the LVL were measured to examine whether RSF can be used as raw materials of adhesive resins for the fabrication of LVL or not. The average moisture content and soaking delamination rate of the LVL bonded with RSF-based adhesive resins exceeded the minimum requirement of KS standard. Moreover, thermal analysis of the RSF-based resins showed similar tendencies except for the RSF-based adhesive resins formulated with pectinase-hydrolyzed RSF. The bending strengths of the LVL were higher than that of the LVL made with commercial PF resins. These results showed the potential of RSF as a raw material of alternative adhesives for the production of LVL. Further works on the optimal conditions of RSF hydrolysis and spreading characteristics for RSF-based adhesive resins is required to improve the adhesive performance of RSF-based resins.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.1
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• pp.49-54
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• 2007

The issue of acid precipitation and related environmental problems in East Asia has been emerging. To evaluate the acidity and chemical characteristics of rainwater in Korea, its chemical properties during cultivation season from April to October in 2005 were investigated at Taean. Also, to estimate the contribution of ions on acidity, ion composition characteristics and neutralization effects by cations were determined. The electrical conductivity balance between measured and estimated values showed a high correlation. Rainwater was highly distributed in the range of pH $4.5{\sim}5.0$. The acidity of rainwater was relatively low during the month of June compared with other monitored periods. $Na^+$ was the main cation, followed by $H^+>Ca^{2+}>NH_4^+>K^+>Mg^{2+}$. Among these ions, $Na^+,\;NH_4^+,\;Ca^{2+}$ and $H^+$ comprised over 94% of the total cations. Rainwater anion composition was more than 80% with $SO_4^{2-}$ and $NO_3^-$. In rainwater samples, $NH_4^+$ and $Ca^{2+}$ contributed greatly to neutralizing the rain acidity. The sulfate content decreased until September, and sea salt derivatives were higher in May and October than during other monitored periods. Also, 78% of the soluble sulfate in rainwater was nss-$SO_4^{2-}$ (non-sea salt sulfate).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.5
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• pp.827-835
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• 2017

With the rapid progress of ageing several issues concurrently occur, and one important social issue that must be resolved is accidents involving Elderly drivers. Efforts to reduce the frequency of such accidents is a must in order to be prepared to face a superaged society. Currently people aged 65 or older are prescribed as an "Elderly person." Therefore, various studies concerning accidents involving Elderly drivers apply this age criteria to separate regular drivers and Elderly drivers. However, there is no criteria to practically discern Elderly drivers with certain physical features as vulnerable road users based on a level of acceptable accuracy. Therefore, this studies intends to compare the possibility of accidents by age group of Elderly drivers by correlation analysis to analyze the accident characteristics by age group. Results showed that for drivers aged 75 and older, their influence on major accident characteristics by vehicle type increased with higher age groups. In particular, passenger cars had a relatively low accident frequency rate for drivers aged between 70 and 80, but for drivers aged 75 to 84, they had higher influence on accidents for the same vehicle type. This demonstrates that as ageing progresses and the average life expectancy increases, the age span of elders continues to increase, meaning that characteristics differ by age group among the aged. This study confirmed that the influence on the possibility of accidents differs by age group among the aged.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.4
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• pp.550-561
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• 2019

Objectives: The purpose of this study is to provide basic data for the improvement of the working environment for health prevention and related countermeasures for shift workers. This study was conducted based on the Fifth Korean Working Conditions Survey (KWCS), which analyzed the health effects of shift work forces and compared them with preceding studies. Methods: By analyzing secondary rates using raw data from the 5th KWCS, 4,870 (9.7%) of the 50,184 total study subjects were divided into shift work and 45,314 (90.3%) non-shift work groups based on the response to shift status. Variables that could affect work health issues were identified and corrected. A cross-analysis was conducted to examine demographic characteristics (gender, age, and education level) of the workers and occupation characteristics (monthly net earnings, employment type, occupation, working period up to now, workplace scale, type of work system, and weekly working hours). In order to find the work health issue ratio between the shift and non-shift work groups, logistic regression was analyzed and the association with health problems according to shift type by gender was looked at through cross-analysis. Results: According to the surveys conducted from the 1st KWCS (2006) to the 5th KWCS (2017), the proportion of shift workers continued to increase. Also, muscular pains in the lower limbs (hips, legs, knees, feet, etc.) (OR=1.135, 95%CI 1.031-1.251), headaches, eyestrain (OR=1.580, 95% CI 1.428-1.748), anxiety (OR=1.715, 95% CI 1.402-2.099), difficulty falling asleep (OR=1.391), and other problems (OR=7.392) were reported. In addition, back pain, muscular pains in shoulders, neck and/or upper limbs, muscular pains in lower limbs (hips, legs, knees, feet, etc.), headaches, eyestrain, depression, anxiety, overall fatigue resulted in significant results for both male and female shift workers. Depression and anxiety were higher in female shift/circulation compared to males. Conclusions: The social nets for the health and safety of shift workers should be explored in a variety of ways, including management and supervision of shift sites, attempts to reorganize and improve the shift system, development of workers' health recovery programs, promotion, systematic treatment, and compensation systems.

• Journal of the Korean Society of Earth Science Education
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• v.9 no.3
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• pp.269-275
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• 2016

This study is conducted to search about changing earth science contents influenced by the scientific literacy from the 7th curriculum to the 2015 revised curriculum. Earth science area is divided into astronomy, geology, meteorology and oceanography contents. Among the elements of scientific literacy, the contents were analyzed focusing on STS elements. In the astronomical and meteorological content areas, there were aspects of scientific literacy in all periods from the 7th to the 2015 revised curriculum. Except for the 2007 revised curriculum in the geological area and the 7th curriculum in the oceanographic content area, the aspects of scientific literacy appeared at all times. It is emphasized the usefulness of science and technology in the astronomical content area and the use of science in everyday life in geological and meteorological content area. In the oceanographic content area, it is emphasized that content of science related social issue such as resource shortage and environmental pollution. This study can be extended to the fields of physics, chemistry and life science, we suggest to inquire the scientific literacy as a integrated science.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.100-105
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• 2016

The use of 3D scanners has increased gradually according to increasing 3D printer applications. The precision inspection of car parts or electronic components is an important issue not only in the field of mass production, but also in small-scale production. Recently, 3D scanner equipment efficiency and recognition technology has been improved continuously. On the other hand, the spraying time to prepare 3D scanning is time-consuming and has environmental problems. Therefore, an automatic spray system has been in demand by the manufacturing industry. Automatic spray equipment was newly developed for the preparation of a 3D scanner. In this research, the automatic spray system guarantees uniform spray operation. To determine the optimal spray parameters, various spraying methods, solutions and conditions were tested and compared with the experiments. The preparation time for 3D scanning was reduced to 1/10 compared to the manual spraying time, and indicates the optimal spraying conditions through a comparison of various spray coating conditions.