• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.6
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• pp.478-488
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• 2023

This paper investigates the naval application of laser communication as a potential replacement for traditional acoustic wave communication in underwater environments. We developed a laser transceiver using Arduino and MATLAB, conducting a water tank experiment to validate communication feasibility across diverse underwater conditions. In the first experiment, when transmitting data through a laser, the desired message was converted into data and transmitted, received, and confirmed to be converted into the correct message. In the second experiment, the operation of communication in underwater situations was confirmed, and in the third experiment, the intensity of light was measured using the CDS illuminance sensor module and the limits of laser communication were measured and confirmed in various underwater situations. Additionally, MATLAB code was employed to gather data on salinity, water temperature, and water depth for calculating turbidity. Optimal wavelength values (532nm, 633nm, 785nm, 1064nm) corresponding to calculated turbidity levels (5, 20, 55, 180) were determined and presented. The study then focuses on analyzing potential applications in naval tactical communication, remote sensing, and underwater drone control. Finally, we propose measures for overcoming current technological limitations and enhancing performance.

• Journal of the Korean Geographical Society
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• v.30 no.2
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• pp.146-168
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• 1995

problems involved in defining and identifying it. However, data on ownership of business establishments may be useful and one of the best alternatives for this empirical research because of use of limited information about control This study examines the spatial patterns of external control in the Korean manufacturing activities between 1986 and 1992. Using the data on ownership iinkages of multilocational firms between 15 administrative areas, it was possible to construct a matrix of organizational control in terms of the number of establishments. The control matrix was disaggregated by three types of manufacturing industries according to the capital and labor requirements of production processes used in. On the basis of the disaggregated control matrix, a series of measures were calculated for investigating the magnitude and direction of control as well as the external dependency. In the past decades Korean industrialization development has risen at a rapid pace, deepening integration into the world economy, together with the continuing growth of the large industrial firms. The expanded scale of large firms led to a spatial separation of production from control, Increasing branch plants in the nation. But recent important changes have occurred in the spatial organization of production by technological development, increasing international competition, and changing local labor markets. These changes have forced firms to reorganize their production structures, resulting in changes of the organizational structures in certain industries and regions. In this context the empirical analysis revealed the following principal trends. In general term, the geography of corporate control in Korea is marked by a twofold pattern of concentration and dispersion. The dominance of Seoul as a major command and control center has been evident over the period, though its overall share of allexternally controlled establishments has decreased from 88% to 79%. And the substantial amount of external control from Seoul has concentrated to the Kyongki and Southeast regions which are well-developed industrial areas. But Seoul's corporate ownership links tend to streteh across the country to the less-developed regions, most of which have shown a significant increase of external dependency during the period 1986-1992. At the same time, a geographic dispersion of corporate control is taking place as Kyongki province and Pusan are developing as new increasingly important command and control reaions. Though these two resions contain a number of branch plants controlled from other locations, they may be increasingly attractive as a headquarters location with increasing locally owned establishments. The geographical patterns of external control observable in each of three types of manufacturing industries were examined in order to distinguish the changing spatial structures of organizational control with respect to the characteristics of the production processes. Labor intensive manufacturing with unskilled iabor experienced the strongest external pressure from foreign competition and a lack of low cost labor. The high pressure expected not only to disinte-grate the production process but also led to location of production facilities in areas of cheap labor. The linkages of control between Seoul and the less-developed regions have slightly increased, while the external dependency of the industrialized regions might be reduced from the tendency of organizational disintegration. Capita1 intensive manufacturing operates under high entry and exit barriers due to capital intensity. The need to increase scale economies ied to an even stronger economic and spatial oncentration of control. The strong geographical oncentration of control might be influenced by orporate and organizational scale economies rather than by locational advantages. Other sectors experience with respect to branch plants of multilocational firms. The policy implications of the increase of external dependency in less-developed regions may be negative because of the very share of unskilled workers and lack of autonomy in decision making. The strong growth of the national economy and a scarcity of labor in core areas have been important factors in this regional decentralization of industries to less-developed regions. But the rather gloomy prospects of the economic growth in the near future could prevent the further industrialization of less-developed areas. A major rethinking of regional policy would have to take place towards a need for a regional policy actively favoring indigenous establishments.

• Progress in Medical Physics
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• v.26 no.4
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• pp.294-303
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• 2015

American Association of Physicists in Medicine (AAPM) Published Task Group 40 report which includes recommendations for comprehensive quality assurance (QA) for medical linear accelerator in 1994 and TG-142 report for recommendation for QA which includes procedures such as intensity-modulated radiotherapy (IMRT), stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT) in 2010. Recently, Nuclear Safety and Security Commission (NSSC) published NSSC notification no. 2015-005 which is "Technological standards for radiation safety of medical field". This notification regulate to establish guidelines for quality assurance which includes organization and job, devices, methods/frequency/tolerances and action levels for QA, and to implement quality assurance in each medical institution. For this reason, all of these facilities using medical machine for patient treatment should establish items, frequencies and tolerances for proper QA for medical treatment machine that use the techniques such as non-IMRT, IMRT and SRS/SBRT, and perform quality assurance. For domestic, however, there are lack of guidelines and reports of Korean Society of Medical Physicists (KSMP) for reference to establish systematic QA report in medical institutes. This report, therefore, suggested comprehensive quality assurance system such as the scheme of quality assurance system, which is considered for domestic conditions, based the notification of NSSC and AAPM TG-142 reports. We think that the quality assurance system suggested for medical linear accelerator also help establishing QA system for another high-precision radiation treatment machines.