• The Journal of Korean Physical Therapy
• /
• v.17 no.2
• /
• pp.22-37
• /
• 2005

This study was performed to investigate LBP(low-back pain) prevalence rate and its related factors inphysical therapists. A self-administered questionnaire survey was conducted to 522 physical therapists in Daegu and Gyeongsangbuk. The LBP prevalence rate for recent 6 months was $61.7\%$. According to age, the prevalence rate was highest in the group aged 24 or less for both male and female physical therapistis. For male physical therapists , it was higher in smokers and drivers, but for female ones, it was not in a significant relationship with smoking and driving. According to work experience, the prevalence rates of those who had been working for less than one year were the highest, and those who had been working at hospitals and clinics were $69.1\%$, significantly high. According to therapy techinque, the prevalence rate related ti PNF was $71.6\%$, the highest and to occupational therapy was $34.3\%$, the lowest. According to working environment for six months, in both male and female physical therapists. LBP prevalence rate was in a statistically significant relationship with work hours during the day, night and weekend duties, repetitive works, motions that bend or twist the waist, the number of patients per day, the number of time to help patients per day, the number of time to carry medical equipment per day and the length of time to work standing. The rate was also higher when physical therapists fekt nire stress from their work. According to the result of multiple logistic regression analysis, male was in a significant relationship with work experience and motions that bend or twist the waist and female was in a significant relationship with work hours during the night and weekend duties, the number of time to help patients per day, motions that bena or twist the waist, actions taken to protect the waist. As for the developmental pattem of LBP in the group of physical therapists with LBP for six moths, $15.7\%$ of them had LBP for first time, $42.3\%$ had recurred LBP, and $42.0\%$ had chronic LBP. As for the causes of LBP, $51.7\%$ said that it was because they worked in the same posture for a long time, and as for how to treat LBP, 48.8% said that they treated themselvs or got help from their co-wokers. The results presented above suggest that physical therapists are exposed to high risk of LBP caused form occupational activities. Therefire, it is necessary to improve working environment to reduce the occurrence of LBP and to develop education programs for preventing the occurrence and recurrence of LBP.

• Journal of Korean Ophthalmic Optics Society
• /
• v.9 no.2
• /
• pp.473-480
• /
• 2004

Recently, they are interested in the relation between night's vehicle accidents of drivers and the dynamic visual acuity at home and aboard. So, in this research, we tried to design an optical system of the inspection equipment to measure the dynamic visual acuity. A optotype standard did to Landolt's ring with 45mm of diameter and 9mm of gap to maintain the visual acuity of 1.0 in the 30m distance. An optical structure of the inspection equipment was composed of the sequence of an observer, a plus refraction lens system, a minus refraction lens system, and an optotype that was arranged to have characteristics that the size of the first virtual image of the optotype made by the minus refraction lens system grows bigger gradually according to the optotype movement to near distance from far distance, and also the first virtual image moves to the principle plane from the focal point of the plus refraction lens system as the size of the first virtual image arranged to the inside of focal distance of plus refraction lens system grows bigger gradually. As doing these processes, we completed the optical system of which characteristic is that the position of the final second virtual image moves to 3m from 50m as the size of the second virtual image made by the plus refraction lens system maintains to be regular.

• Korean Journal of Remote Sensing
• /
• v.28 no.1
• /
• pp.79-93
• /
• 2012

This paper suggests a system architecture for the advanced meteorological satellite image processing system that is developing by NMSC(National Meteorological Satellite Center). The meteorology satellite image processing system has basically the image acquisition, the image processing, the data management, and the data dissemination functionalities. However, the existing system has some problems with respect to system integration as well as maintenance to accommodate new satellites and/or the new image processing systems for them which will be developed in the near future. To cope with these problems we propose a new system architecture for the advanced meteorology satellite image processing system. To do this we select as the architectural drivers the quality attributes such as modifiability, inter-operability, extendability, reusability, and platform independency and design the architecture to achieve such quality attributes. We expect that the new approach will solve current issues such as system integration, system dependency, or data management problems and will provide easy ways to incorporate new systems and to maintain them.

• Korean Security Journal
• /
• no.13
• /
• pp.383-402
• /
• 2007

World security market has continuously been growing since the 2000s. The growth rate seems to reach up to 7-8% annually. What is more, Korea is expected to be one of the most rapidly developing markets, Based of this view, this research investigates the principal drivers to have affected on the expansion of Korean security market over the past 20 years. In addition to that, this study also examines the influence of recent changes in the world economy and globalization, socio-demographic change, development of information technology on the future security market. The data reviewed in this study are official crime rates, socio-economic indicators, statistics from the National Police Agency and the business reports of a leading private security company. This study shows that several factors such as rising crime rates, lack of police capacities, national economic growth and rising household income have played important roles in development of Korean market. It is also expected to keep those positive affects on the future market. On the other side, in recent years, the security market seems to be increasingly affected by new social economic changes. Those are impact of last aging society, rapid increase of individual household and women's participation in labor market. These factors seem to increase personal and household needs for security service. World economy, globalization process and development of information technology are also deemed to give rise to social demands for surveillance, monitoring service and security in cyber space.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.46 no.10
• /
• pp.867-875
• /
• 2018

Conventional nylon wire cutting-type holding and release mechanisms (HRMs) are limited to securely hold the solar panel under launch environment as the size of the panel increases because the nylon wire is tightened directly on the surface of the solar panel. In this study, we proposed a nylon wire cutting-type HRM for 6U CubeSat's solar panel applying elliptic-shaped bracket with a Ball & Socket interface. The proposed HRM has the advantage of higher holding capability along in-plane and out-of plane directions of solar panel and simplicity in tightening process of nylon wire. The design drivers of structural design of CubeSat's solar panel with the proposed HRM were defined by structural analysis under launch loads. In addition, The design effectiveness of the proposed HRM was verified through the functional tests according to the thickness of nylon wire and the number of wire winding under various temperature conditions.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.10
• /
• pp.1359-1366
• /
• 2010

Recently, many electronic control techniques for vehicles have been developed and applied. One of the technologies can be X-by-wire such as throttle-by-wire, brake-by-wire, steer-by-wire, and etc, in which most of mechanical parts are replaced into electrical wire and actuators. In this study, the effect of throttle-by-wire and brake-by-wire control systems on vehicle velocity control, especially in a school zone, are taken into consideration. The number of accidents reported in school zones is higher than that in other places. The reason for this is that many vehicle drivers do not obey speed limit regulations. Moreover, some of the students are careless while crossing the streets. Therefore, in this study, we attempt to develop a method using throttle-by-wire and brake-by-wire control systems for automatically reducing the vehicle speed such that it will be within the speed limit. First, an engine model and a transmission system model are developed for a specific vehicle model. Second, speed reduction is carried out such that the reduction follows a pre-designed cubic spline trajectory; the trajectory is determined such that rapid deceleration, which causes discomfort to the driver and passengers, can be prevented, for which a fuzzy-PID control algorithm is applied for the trajectory following control. Finally, simulation results are presented to verify the performance of the proposed speed reduction control system.

• Journal of Korean Society of Transportation
• /
• v.23 no.7 s.85
• /
• pp.17-33
• /
• 2005

Highway design speed is a very important design element which determines highway design level. When determining highway design speed, one would estimate it utilizing the most likelihood of design speed and vehicle operating speed relationship. Existing operating speed prediction models only include highway geometric characteristics and their impacts on speed, which usually can not consider the impact of highway design speed on surrounding roadway environment and land use pattern. If this happens, excessive highway construction cost and huge environmental impact can occur. In this research project, a new vehicle operating speed prediction model was developed which can reflect the effect of surrounding roadway environment into vehicle speed prediction. The followings are the research findings : Firstly, highway terrain types and land use pattern on national roads were classified and integrated into drivers' visual recognition pattern. This was performed using a data management software. Secondly, the developed highway terrain types and land use pattern were related to vehicle speeds and it was found that there were significant statistical differences among vehicle speed for each different terrain and land use pattern. Thirdly. the General Linear Model analysis was employed to analyze the effects of highway geometric features, terrain types, and land use patterns. For two-lane highway and four-lane highway tested in this research project, it was found that R squares were 0.67 and 0.85, respectively. Additionally an optimal highway design speed range table, based on this research project. was proposed for practical use. This table can be reliably used on South Korean national road design, but discretion is required for applying this table to other types of highways including provincial roads and municipal roads.

• Journal of Korean Society of Transportation
• /
• v.22 no.2 s.73
• /
• pp.131-143
• /
• 2004

Given a path represented by a sequence of link numbers in a graph, the vine is differentiated from the loop in a sense that any link number can be visited in the path no more than once, while more than once in the loop. The vine provides a proper idea on complicated travel patterns such as U-turn and P-turn witnessed near intersections in urban transportation networks. Application of the link label method(LLM) to the shortest Path algorithms(SPA) enables to take into account these vine travel features. This study aims at expanding the LLM to a K-th path search algorithm (KPSA), which adopts the node-based-label correcting method to find a group of K number of paths. The paths including the vine type of travels are conceptualized as drivers reasonable route choice behaviors(RRCB) based on non-repetition of the same link in the paths, and the link-label-based MPSA is proposed on the basis of the RRCB. The small-scaled network test shows that the algorithm sequence works correctly producing multiple paths satisfying the RRCB. The large-scaled network study detects the solution degeneration (SD) problem in case the number of paths (K) is not sufficient enough, and the (K-1) dimension algorithm is developed to prevent the SD from the 1st path of each link, so that it may be applied as reasonable alternative route information tool, an important requirement of which is if it can generate small number of distinct alternative paths.

• Journal of Korean Society of Transportation
• /
• v.22 no.2 s.73
• /
• pp.145-154
• /
• 2004

The growing demand for customer-responsive, made-to-order manufacturing is stimulating the need for improved dynamic decision-making processes in commercial fleet operations. Moreover, the rapid growth of electronic commerce through the internet is also requiring advanced and precise real-time operation of vehicle fleets. Accompanying these demand side developments/pressures, the growing availability of technologies such as AVL(Automatic Vehicle Location) systems and continuous two-way communication devices is driving developments on the supply side. These technologies enable the dispatcher to identify the current location of trucks and to communicate with drivers in real time affording the carrier fleet dispatcher the opportunity to dynamically respond to changes in demand, driver and vehicle availability, as well as traffic network conditions. This research investigates key aspects of real time dynamic routing and scheduling problems in fleet operation particularly in a truckload pickup-and-delivery problem under various settings, in which information of stochastic demands is revealed on a continuous basis, i.e., as the scheduled routes are executed. The most promising solution strategies for dealing with this real-time problem are analyzed and integrated. Furthermore, this research develops. analyzes, and implements hybrid algorithms for solving them, which combine fast local heuristic approach with an optimization-based approach. In addition, various partitioning algorithms being able to deal with large fleet of vehicles are developed based on 'divided & conquer' technique. Simulation experiments are developed and conducted to evaluate the performance of these algorithms.

• Journal of Korean Society of Transportation
• /
• v.22 no.4 s.75
• /
• pp.97-106
• /
• 2004

It is a Known fact that driving through long tunnel increases possibility of traffic accident because of psychological feeling of insecurity and dispersion of drivers' concentration since driving in narrow and limited space for a longtime. It, therefore, results in raising transportation and environment problems, such as traffic accident difficult to be properly dealt with and ventilation. This study aims at proposing a method of augmenting driving amenity by improving the internal lighting facilities in the tunnel. The study is conducted by investigating internal landscapes of tunnels by lighting colors, which are currently being operated. The Color Planning System (CPS), developed by SHARP Co. Ltd, is exploited for selecting adjective that express the sensitivity image on lighting colors. The CPS is an example that applies to sensitivity of human body for products design development. The CPS takes the following process to define the color : 1) expressing "Pvoduct's Image" as "A Word (adjective)" and 2) referring "A Word" to "Image Scale", and 3) determining the color through this "Image Panel". The study is processed by making a questionnaire using the semantic differential (SD) scale, grasping the consciousness structure of experimental persons through the Factor Analysis, and building a model in which dependent variable is "Degree of Preference" about internal landscape in tunnel using LISREL(LInear Structural RELations).