• Journal of Korean Society of Forest Science
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• v.96 no.1
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• pp.7-13
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• 2007

This study was done to develop PDA based application system for forest geographic information with GPS. The major results obtained in this study were as follows. A PDA based application program was developed to work on $Microsoft^{TM}$ PocketPC 2002 and 2003 operating system. The screen of PDA displays a 1:25,000 digital topographical map adopted DXF format converted from PC, and the map data with 1:2,500 to 1:30,000 on PDA can be zoomed in or out to five levels. Current position and navigating path received from GPS can be displayed on the screen and be saved in PDA. Information selected among layers of digital topographic map in DXF format can be converted into binary files which can be used on forest geographic information software. This can compress DXF files to 90% in size, and the processing speed of PDA was improved. The forest geographic information management system can be used to manage sample plots on which forest inventory is done, with the help of the sub-menus and grid index values with position information received from GPS. Forest workers can in quire forest geographic information such as forest type, location, forest roads, soil erosion control dams using forest geographic information management system in the field. The forest geographic information management system can provide current position and mobile path information to people who enjoy forest related activities like mountain-climbing, sightseeing, and visiting to historic spots.

• Journal of Biosystems Engineering
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• v.38 no.2
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• pp.138-148
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• 2013

Purpose: Determining an appropriate path is a top priority in order for a robot to maneuver in a dynamically efficient way especially in a pick-and-place task. In a non-standardized work environment, current robot arm executes its motion based on the kinematic displacements of joint variables, though resulting motion is not dynamically optimal. In this research we suggest analyzing and applying motion patterns of the human arm as an alternative to perform near optimum motion trajectory for arbitrary pick-and-place tasks. Methods: Since the motion of a human arm is very complicated and diverse, it was simplified into two links: one from the shoulder to the elbow, and the other from the elbow to the hand. Motion patterns were then divided into horizontal and vertical components and further analyzed using kinematic and dynamic methods. The kinematic analysis was performed based on the D-H parameters and the dynamic analysis was carried out to calculate various parameters such as velocity, acceleration, torque, and energy using the Newton-Euler equation of motion and Lagrange's equation. In an attempt to assess the efficacy of the analyzed human motion pattern it was compared to the virtual motion pattern created by the joint interpolation method. Results: To demonstrate the efficacy of the human arm motion mechanical and dynamical analyses were performed, followed by the comparison with the virtual robot motion path that was created by the joint interpolation method. Consequently, the human arm was observed to be in motion while the elbow was bent. In return this contributed to the increase of the manipulability and decrease of gravity and torque being exerted on the elbow. In addition, the energy required for the motion decreased. Such phenomenon was more apparent under vertical motion than horizontal motion patterns, and in shorter paths than in longer ones. Thus, one can minimize the abrasion of joints by lowering the stress applied to the bones, muscles, and joints. From the perspectives of energy and durability, the robot arm will be able to utilize its motor most effectively by adopting the motion pattern of human arm. Conclusions: By applying the motion pattern of human arm to the robot arm motion, increase in efficiency and durability is expected, which will eventually produce robots capable of moving in an energy-efficient manner.

• Korean Journal of Social Welfare
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• v.58 no.2
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• pp.57-85
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• 2006

This study tries to understand how the physical impairment develops to practical disabilities among adults with cerebral palsy through path analysis, based on the concept of disability by WHO that the physical impairment and "activities of daily living"(ADL) are affected by the combination of interrelated concept of personal health and environment. Pain and instrumental support are conceptualized as mediating variables for ADL among the adults with cerebral palsy, which are used in the analysis. As a result of surveying of 381 participants, paralyzed region is the only variable directly influencing ADL; other variables such as gender, age, and types of cerebral palsy do not have direct effect on ADL. However, it turns out that age, types of cerebral palsy, and paralyzed region influence on pain problems and also on ADL indirectly, when pain is introduced as a mediating variable. The study also shows that the extent of instrumental support works directly and indirectly toward pain and ADL. It means that individual impairment does not necessarily have influence on the limitations of ADL, but on the result of interrelatedness of individual factors and social factors. Finally, this study implies that the social work practice should be intervened with a new approach of the consideration of the effects of mediating variables.

• Journal of Communications and Networks
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• v.16 no.2
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• pp.227-237
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• 2014

Throughput scaling laws for two coexisting ad hoc networks with m primary users (PUs) and n secondary users (SUs) randomly distributed in an unit area have been widely studied. Early work showed that the secondary network performs as well as stand-alone networks, namely, the per-node throughput of the secondary networks is ${\Theta}(1/\sqrt{n{\log}n})$. In this paper, we show that by exploiting directional spectrum opportunities in secondary network, the throughput of secondary network can be improved. If the beamwidth of secondary transmitter (TX)'s main lobe is ${\delta}=o(1/{\log}n)$, SUs can achieve a per-node throughput of ${\Theta}(1/\sqrt{n{\log}n})$ for directional transmission and omni reception (DTOR), which is ${\Theta}({\log}n)$ times higher than the throughput with-out directional transmission. On the contrary, if ${\delta}={\omega}(1/{\log}n)$, the throughput gain of SUs is $2{\pi}/{\delta}$ for DTOR compared with the throughput without directional antennas. Similarly, we have derived the throughput for other cases of directional transmission. The connectivity is another critical metric to evaluate the performance of random ad hoc networks. The relation between the number of SUs n and the number of PUs m is assumed to be $n=m^{\beta}$. We show that with the HDP-VDP routing scheme, which is widely employed in the analysis of throughput scaling laws of ad hoc networks, the connectivity of a single SU can be guaranteed when ${\beta}$ > 1, and the connectivity of a single secondary path can be guaranteed when ${\beta}$ > 2. While circumventing routing can improve the connectivity of cognitive radio ad hoc network, we verify that the connectivity of a single SU as well as a single secondary path can be guaranteed when ${\beta}$ > 1. Thus, to achieve the connectivity of secondary networks, the density of SUs should be (asymptotically) bigger than that of PUs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.317-325
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• 2020

Using a structural model, this study aims to verify the association between job stress, burnout, and self-efficacy levels of health teachers responsible for school health. Structured questionnaires were administered to 814 health teachers, and validated through Structural Equation Modeling (SEM). The study results show that job stress of the health teacher was 2.9±0.64 and burnout was 2.6±0.52, which was slightly lower than the median of the Likert 5-point scale, while self-efficacy was 4.1±0.51. Various sub-factors contributed to the scores: 'student and family' and 'peer teacher's perception' were high for job stress, while 'work in charge' was high for burnout. Job stress of health teachers resulted in increased burnout and decreased self-efficacy. Furthermore, increased burnout significantly decreased self-efficacy. Hence, job stress affected burnout, and burnout affected self-efficacy. Our data clearly demonstrates that job stress is very important to reduce burnout of health teachers and increase their self-efficacy. Therefore, various efforts are required to lower job stress. This study will help to establish new policies and practical improvement plans to reduce job stress and exhaustion of health teachers, and consequently increase their self-efficacy.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.2
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• pp.143-152
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• 2021

Recently, universities are being requested to educate a wider range of technical and social skills in order to respond to the government's policy for promoting youth employment and the industrial demand arising from social changes. Accordingly, field practice at universities is being further strengthened. It is important to analyze whether the work experience and information that students gained through field practice can improve their confidence in their career path, and can serve as a motive for not only employment but also start-up after graduation. In this study, the motivational aspect which leads to action by improving students' confidence in their career path is investigated. In addition, the influence of field practice experience on employability and entrepreneurial intention is also analyzed by setting a self-directed career attitude as a variables. The results of this study are as follows. First, the field practice experience of college students has a significant effect on employability, but does not directly affect their entrepreneurial intention. Second, it is confirmed that the higher the self-directed career attitude of students with experience of field practice has a positive (+) effect on the employability. Third, the higher the self-directed career attitude has also a positive (+) effect on entrepreneurial intention. This study shows the influence of field practice on employability and entrepreneurial intention beyond the limit of the existing research that was divided into employment and start-up. Theoretical basis for analyzing whether universities can achieve practical results simultaneously in government policy for employment and start-up is also provided.

• Korean Journal of Forensic Psychology
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• v.13 no.1
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• pp.75-97
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• 2022

Profiling is recognized as a representative application area of domestic criminal psychology, and the National Police Agency profiler is firmly established as a profession. However, compared to the social awareness, the recognition and utilization within the police is not high. In this study, we tried to identify factors affecting the intention to use profiling by identifying the perception of investigators who request and use profiling from a profiler when a violent incident occurs. To this end, the relationship between the perception of the importance of factors considered by investigators in the criminal investigation process and the attitude toward profiling on the intention to use profiling was verified through the path model. As a result of a survey of 340 police investigators, the investigator's perception of the importance of investigation elements was divided into two factors: the importance of normative investigative elements (evidence collection and legal judgment, etc.) and factual investigative elements (criminal analysis, criminal information system analysis, etc.). Among them, the importance of factual investigative elements were found to have a positive effect on the intention to use it by mediating the attitude toward profiling. On the other hand, in the case of the importance of normative investigative elements, it was found to have a negative effect on the attitude toward profiling. These results suggest that the perception that investigators have about investigation, which is their main work area, plays a role in determining whether to request profiling as well as attitude towards profiling. Based on the research results, strategies necessary to activate the use of profiling were discussed.

• Tunnel and Underground Space
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• v.32 no.5
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• pp.298-311
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• 2022

Some problems, such as aging workers, a decreased population due to a low birth rate, and shortage of skilled workers, are rising in construction sites. Therefore research for smart construction technology that can be improved for productivity, safety, and quality has been recently developed with government support by replacing traditional construction technology with advanced digital technology. In particular, the motor grader that mainly performs road surface flattening is a construction machine that requires the application of automation technology for repetitive construction. It is predicted that the construction period will be shortened if the construction automation technology such as trajectory tracking, automation work, and remote control technology is applied. In this study, we introduce the hardware and software architecture of the smart motor grader to apply unmanned and automation technology and then analyze the traditional earthwork method of the motor grader. We suggested the application plans for the path pattern and blade control method of the smart motor grader based on this. In addition, we verified the performance of waypoint-based path-following depending on scenarios and the blade control's performance through tests.

• The Journal of the Korea Contents Association
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• v.22 no.8
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• pp.557-569
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• 2022

The purpose of this study is intended to identify the mediated moderating effect including the mediating effect of job satisfaction and moderating effect of job expectations in the relation between work value, job satisfaction, In this study, the mediating effect of job satisfaction and job preference on the relationship between job value and quality of life were investigated. In this study, questions to measure job value, job satisfaction, and job preference were examined using GOMS data, and data analysis was performed using SPSS 23.0 and SPSS Macro. Since the mediated moderation model is an integrated model that includes mediating and moderating effects, the mediating effect, the moderating effect, and the mediated moderation effect were sequentially verified. As a result of the study, first, it was confirmed that the mediating effect model through job satisfaction was statistically significant. Next, it was confirmed that job value had a statistically significant effect on life satisfaction through the direct path and the indirect path through job satisfaction as a mediating variable. Third, it was confirmed that the moderated mediating effect model of job preference through job satisfaction was statistically significant. In detail, job value as an independent variables and job satisfaction as a mediating variable were found to have a statistically significant positive (+) effect on the dependent variable, quality of life.

• Journal of The Korean Association For Science Education
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• v.28 no.6
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• pp.649-663
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• 2008

The purpose of this study was to compare the processes of making hypotheses concerning the anomalous path of Wukong, a typhoon that came close to Korea recently, between an earth scientist and undergraduate students. Data were obtained through interviews with a practicing earth scientist as well as five undergraduate students. Inquiry reports of the students were also analysed. The result showed that while the earth scientist conducted a case study with already-established models of typhoon, the students were enabled to work on the specific case of Wukong only after they learned general theories on typhoons. Background knowledge played an important role for the scientist and students to formulate scientific hypotheses. Both the earth scientist and undergraduate students generate multiple working hypotheses, and they considered a couple of conditions to select more plausible hypotheses, including theoretical coherence, causative processes, and consistency with empirical data. Despite these similarities, there were differences in the scope and depth of background knowledge between the scientist and students. In addition, it was not likely that the undergraduate students possessed explicit perceptions of the conditions which could make a hypothesis more probable, except for the empirical consistency. Implications for science education and relevant research were discussed.