• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.3
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• pp.175-183
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• 2008

In wireless sensor networks with ad hoc networking capability, sensor nodes are battery operated and are usually disposable once deployed. As a result, each sensor node senses and communicates with limited energy and, thus, energy efficiency has been studied as a key design factor which determines lifetime of a wireless sensor network, and it is more improved recently by using so-called cross-layer optimization technique. In this paper, we propose and implement a new energy saving mechanism that reduces energy consumption during data collection by controlling transmission power at sensor nodes and then measure its performance in terms of lifetime improvement for the wireless sensor network platform ZigbeX. When every sensor node transmits sensed data to its clusterhead, it controls its transmission power down to as low level as communication is possible, resulting in energy saving. Each sensor node controls its transmission power based on RSSI(Received Signal Strength Indicator) of the packet received from its clusterhead. In other words, the sensor node can save energy by controlling its transmission power down to an appropriate level that its clusterhead safely receives the packet it transmits. According to the repetitive experiment of the proposed scheme on the ZigbeX platform using the packet analyzer developed by us, it is observed that the network lifetime is prolonged by up to 21.9% by saying energy during the data collection occupying most amount of network traffic.

• Journal of Korean Society of Transportation
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• v.24 no.7 s.93
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• pp.41-51
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• 2006

In this paper, a fundamental study on the characteristics of traffic accidents according to the alignment and traffic conditions on the ramp of freeway is addressed. The macro-and-micro scope analysis of characteristics about traffic accidents on the trumpet-IC ramps is conducted depending on the entering and exit ramp types under the various conditions of traffic volume and alignment And it is turned out that the conditions of alignment. such as radius, differences of curvatures, and main road grade, and traffic volume relate to the ramp accidents of trumpet IC according to ramp types, such as direction, semi-direction, and loop. Macroscopically, AR (Accident Rate) according to trumpet IC types, A and B, is analyzed nearly equal, but Number of accidents occurred in IC type B shows about 1.5 times higher than type A. And AR of exit ramps shows three times more than entrance ramps. Microscopically, ARs for each exit-ramp type, according to the increment of traffic volume, the difference of curvatures. and the first radius, exponentially decrease respectively. But relationships between AR and the second radius or exit ramp shows inverted U-shaped. AR according to main-road grade Peaks between -1.5% and -0.5%. It is expected that the developed models not only are employed to make design of trumpet-IC ramp more cost-efficiently and safely, but also contribute to making alternatives to the reduction of traffic accidents on trumpet IC ramps under the conditions of high traffic accident rate.

• Tunnel and Underground Space
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• v.25 no.1
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• pp.97-106
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• 2015

We must precisely investigate the mechanical characters of rock to design rock slope safely and efficiently. But the method of clinometer has some disadvantages. So, we need a new measurement that can replace the method of clinometer. In this study, we analyze the reliability of joint orientation measurements in rock slope using the 3D laser scanner and program Split-FX that is a point cloud data analysis software. We could acquire the 495 pieces joint data through the automatic extraction of features. And we confirmed that there were some errors occurred with ${\pm}4^{\circ}$ of dip and ${\pm}5^{\circ}$ of dip direction. Generally, the method of clinometer has ${\pm}5^{\circ}$ and ${\pm}10^{\circ}$ error ranges of the joint orientation(dip/dip direction) that are the results of the advance research. Therefore, we analyzed the method of 3D laser scanner, and it is found to be efficient, reliable. This method is expected to mend the disadvantages of Clinometer method.

• Informatization Policy
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• v.28 no.4
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• pp.54-75
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• 2021

The right to data portability needs to be introduced to strengthen the self-control of data subjects and promote personal data use. However, the right to data portability constitutes a high risk of invasion of privacy of data subjects and may infringe on the property rights of data controllers, so careful and thorough design is warranted. The right to data portability can intensify the concentration and monopoly of personal data, result in problems of overseas transfer of personal data held by public institutions, and enrich only the profits of giant platforms by burdening the data subject with high transfer cost. By contrast, SMEs are more likely to endure a personal data deprivation. From the proposed amendment to the Personal Data Protection Act are raised various legal issues such as. i) Whether to include inferred/derived data, personal data held by public institutions, activity data, sensitive data, and personal data of third parties within the scope of data portability; ii) whether SMEs are included in the data porting organization; iii) whether to exclude SMEs or large platforms from the scope of the data receiving organization; iv) Whether to allow the right to transmit to other data controllers, v) Whether to allow the overseas transfer of personal data held by public institutions, vi) How to safely exercise the right to data portability, vii) the scope of responsibility and immunity of a data porting organization, etc. The purpose of this paper is to propose the direction for legislative action based on various legal issues related to data portability.

• Journal of Industrial Convergence
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• v.20 no.11
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• pp.85-93
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• 2022

As of the end of 2019, the total population nationwide was 51,849,861, and over the past five years, the population per household has decreased by 1.52% annually from 2.45 in 2015 to 2.31 in 2019. Looking at the current status of population distribution by age group, Busan metropolitan city had the highest proportion of senior citizens aged 65 or older at 18.2%, and Sejong Special Self-Governing city had the lowest at 9.4%. In particular, as of 2019, the population of the mobility handicapped was 15,219,000 nationwide, showing a ratio of about 29.4% of the total population. Therefore, it is important to secure the right to move according to the mobile facilities so that the mobility handicapped can move safely and conveniently. Against this background, this study places value on transportation welfare facilities centered on the mobility handicapped for safe and convenient movement, and in particular, in proposing measures to cope with the entry of an aging society and the continuous increase of the mobility handicapped, the transportation facilities, The purpose of this study is to analyze the impact of welfare facilities on the mobility handicapped and suggest implications. As a research method, the results of statistical analysis methods were presented through major preceding studies and expert surveys.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.67-72
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• 2006

Injection of $CO_2$ into underground saline formations, due to their large storage capacity, is probably the most promising approach for the reduction of $CO_2$ emissions into the atmosphere. $CO_2$ storage must be carefully planned and monitored to ensure that the $CO_2$ is safely retained in the formation for periods of at least thousands of years. Seismic methods, particularly for offshore reservoirs, are the primary tool for monitoring the injection process and distribution of $CO_2$ in the reservoir over time provided that reservoir properties are favourable. Seismic methods are equally essential for the characterisation of a potential trap, determining the reservoir properties, and estimating its capacity. Hence, an assessment of the change in seismic response to $CO_2$ storage needs to be carried out at a very early stage. This must be revisited at later stages, to assess potential changes in seismic response arising from changes in fluid properties or mineral composition that may arise from chemical interactions between the host rock and the $CO_2$. Thus, carefully structured modelling of the seismic response changes caused by injection of $CO_2$ into a reservoir over time helps in the design of a long-term monitoring program. For that purpose we have developed a Graphical User Interface (GUI) driven rock physics simulator, designed to model both short and long-term 4D seismic responses to injected $CO_2$. The application incorporates $CO_2$ phase changes, local pressure and temperature changes. chemical reactions and mineral precipitation. By incorporating anisotropic Gassmann equations into the simulator, the seismic response of faults and fractures reactivated by $CO_2$ can also be predicted. We show field examples (potential $CO_2$ sequestration sites offshore and onshore) where we have tested our rock physics simulator. 4D seismic responses are modelled to help design the monitoring program.

• Research in Community and Public Health Nursing
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• v.6 no.1
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• pp.55-73
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• 1995

An Effect of Muscle Strength Training Program on Muscle Strength, Muscle Endurance, Instrumental Activities of Daily Living and Quality of Life in the Institutionalized Elderly Recent statistics shows that the aged are the fastest growing segment of our population by increasing life span. The age group of over 60 shows multiple health problems and the most serious handicapping problem of these. are related to the changes in muscular skeletal system. With aging, people lose. their muscle mass and muscle strength resulting from biological changes and physical inactivity. Studies documented a 30-50% loss of muscle mass in an advanced age and thus, ordinary life activities can be seriously affected due to weakened muscle strength. Preservation of muscle strength of lower limb is especially important in the aged. Since it is readily affected from reduced physical activity in old age, sometimes to the detriment of moving or walking. So muscle strength exercise program designed for the elderly to improve leg muscle strength and leg muscle endurance. The research design used was nonequivalent control group pretest - protest design. The purposes of this study were to test the effect of muscle strength exercise program utilizing Leg Press on muscle strength, muscle endurance, instrumental activities of daily living(IADL), cognitive perceptual variables and quality of life. Forty nine subjects participating in this study consisted of twenty four male and twenty five female. Twenty four experimental group subjects were selected from C-institution in Chung Buk province, and twenty five control group subjects were selected from O-institution in Chung Nam province. The mean age of subjects was 72.8 years. Muscle strength training program utilizing Leg Press for the experimental group was carried out three times a week for 9 weeks. The data was collected from August, 1993 to October, 1993. Data were analyzed with $X^2-test$, t-test, ANCOVA test, Kruskal Wallis 1-Way ANOVA test using SPSS PC program. Results were obtained as follows : 1) The experimental group showed significantly higher scores on muscle strength (leg lift strength, back lift strength and grip strength) and muscle endurance than control group after the experiment $\ulcorner$F=52.35(p=.001), F=54.07(p=.001), F=6.97(p=.011), F=18.17(p=.001)$\lrcorner$ 2) Experimental group were significantly higher scores on IADL than control group(F=7.51, p=.009). 3) Experimental group showed significantly higher scores on economical state and self esteem aspects of the quality of life scale than control group $\ulcorner$F=10.59(p=.002), F=6.97(p=.011)$\lrcorner$. But there were no differences in emotional state, physical and functional state and relationship with reatives in the quality of life between groups. 4) Scores on IADL showed a significant difference with the level of muscle strength and muscle endurance $\ulcornerx^2=7.73(p=.025),\;x^2=8.86\;(p=.011)\lrcorner$ 5) Scores on self esteem and physical and functional state aspects of the quality of life scale showed a significant difference with the level of IADL $\ulcornerx^2=11.39(p=.003),\;x^2=9.02(p=.011)\lrcorner$. 6) Scores of experimental group after the experiment in cognitive perceptual variables (perceived benefit on exercise, perceived health status, self efficacy, emotion on exercise) were significantly higher than those of control group $\ulcorner$F=32.09(p=.001), F=5.07(p=.029), F=20.63 (p=.001), F=30.38(p=.001)$\lrcorner$. As a result of this study, the effect of strength training exercise program with Leg. Press had improved muscle strength, muscle endurance, IADL, and the perception of self esteem, physical and funtional state, and economical state. Thus strength training program could be beneficially applied for the prevention of disablity and promotion of health and wellbeing in the aged easily and safely. The subjects in the experimental group have maintained their exercises till six months after the cessation of the experiment. This seem to illustrate that changes in cognitive perceptual variables and the improvement in health status have reinforced motivation for the continuation of voluntary exercises. A further study is necessary to determine the factors affecting maintainance of muscle strength exercise and to assess the effect of weight training program on bone density.

• Journal of the Korean GEO-environmental Society
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• v.13 no.9
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• pp.17-29
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• 2012

To investigate the characteristics of shear strength and soil deformation in soft grounds, in which various vertical drains were placed, two hundreds field monitoring data of embankments performed in thirteen road construction sites at west and south coastal areas of the Korean Peninsula were collected. At first, the relationship between settlement and lateral displacement was investigated into three stages, in which embankment construction works were divided into initial filling stage, final filling stage and stage after complete filling. And then, the relationship of surcharge pressures and embankment heights with undrained shear strength of soft grounds were investigated. The investigation on settlement and lateral displacement illustrated that the increment of lateral flow to the increment of settlement was low during initial filling stage, but increased gradually with filling and showed largest during final filling stage. After complete filling, the lateral displacement was converged, even though the settlement was increased continuously. Therefore, most of lateral flow was occurred during embankment filling. The ratio of the lateral displacement increment to the settlement increment was 20% for initial filling stage, which coincided with the one presented by Tavenas et al.(1979), but became 50% for final filling stage, which was half of the one presented by Tavenas et al.(1979). However, the ratio reduced to 1% to 9%, which was quite lower than the one presented by Tavenas et al.(1979). Shear deformations, even shear failures, were predicted in soft grounds under initial undrained shear strength, since the design heights of embankments were higher than the yield height in all the sites. However, embankment construction would be possible since the yield height became higher than the design height due to improvement of shear strength of soft grounds with application of the vertical drains. In order to perform safely embankments for road constructions, the embankment loads should be designed not to be exceed 5.14 times the initial undrained shear strength of soft grounds and to be less than 3.0 times the undrained shear strength improved with application of vertical drains in soft grounds.

• Fire Science and Engineering
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• v.17 no.4
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• pp.76-85
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• 2003

In this study, we write down the definitions, their causes and the techniques of analysis as a theoretical consideration of common cause failures, and investigate the limitation and the importance of the common cause failures by applying to the analysis on the fire protection as a representative safety facility. As you can know in the reliability analysis, most impressive cause is the malfunctions of pumping operations; especially the common cause failure of two pumps is dominant. In other words, it is possible to assess system-reliability as twice as actual without CCF From these, CCF is extraordinarily important and the results are highly dependent on the CCF factor. And although it would increase with multiple installations, the reliability are not defined as linear with those multiplications. In addition, the differences in results due to the models for analysis are not significant, whereas the various sources of data produce highly different results. Therefore, we conclude that the reliabilities are dependent on the quality of the usable data much better than the variety of models. As a result, the basic and engineering device for the preventions of CCF of the multiple facilities is to design it as reliably as to design the fire-water pump. That is to say, we must assess those reliabilities using PFD whether they are appropriate to SIL (Safety Integrity Level) which is required for the reliability in SIS (Safety Instrumented System). The result of the analysis on the reliability of the fire-water supply with CCF shows that PFD is 3.80E-3, so that it cannot be said to be designed as safely as in the level of SIL5. However, without CCF, PFD is 1.82E-3 which means that they are designed as unsafely as before.

• The Korean Journal of Air & Space Law and Policy
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• v.35 no.3
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• pp.151-208
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• 2020

Japan's two outer space-related laws were promulgated on November 16, 2016. There are the Act on Launching of Spacecraft, etc. and Control of Spacecraft (Act No. 76 of 2016, Space Activities Act) and the Act on Securing Proper Handling of Satellite Remote Sensing Records (Act No.77 of 2016, Remote Sensing Records Act). Japan's Space Activities Act states that a person who launches a satellite from the territory of Japan, or from a ship or airplane registered in Japan, must obtain permission from the Prime Minister prior to the launch. To obtain the permission, the person must have a certificate for a rocket design and for radio equipment at a launching facility. In addition, the ability to launch a rocket safely and the purpose for the satellite launch must be evaluated. Managing a satellite from Japan also requires permission from the government. A person who launches a rocket must have insurance for any potential damage arising from accidents, and the government is to supplement the potential compensation to allow for damage that cannot be covered by private insurance. The purpose of this paper reviews regulations of launch services and management of satellites in the Japan's Space Activities Act. It also offers some implications and suggestions for regulations of launching of spacecraft and management or operation of satellites.