• The KIPS Transactions:PartC
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• v.13C no.5 s.108
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• pp.541-548
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• 2006

Sensor network is a network for realizing the ubiquitous computing circumstances, which aggregates data by means of observation or detection deployed at the inaccessible places with the capacities of sensing and communication. To realize this circumstance, data which sensor nodes gathered from sensor networks are delivered to users, in which it is required to encrypt the data for the guarantee of secure communications. Therefore, it is needed to design key management scheme for encoding appropriate to the sensor nodes which feature continual data transfer, limited capacity of computation and storage and battery usage. We propose a key management scheme which is appropriate to sensor networks organizing hierarchical architecture. Because sensor nodes send data to their parent node, we can reduce routing energy. We assume that sensor nodes have different security levels by their levels in hierarchy. Our key management scheme provides different key establishment protocols according to the security levels of the sensor nodes. We reduce the number of sensor nodes which share the same key for encryption so that we reduce the damage by key exposure. Also, we propose key update protocols which take different terms for each level to update established keys efficiently for secure data encoding.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.6
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• pp.39-47
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• 2010

The coastal area is the place where two conflicting values provide opportunities for recreation, tourism and conservation of the natural environment. Most of these coastal areas have been disregarded in terms of tourism because of the high value placed on natural resources. Management strategy has usually been first on the priority list of natural. resources. However, due to the significant number of visitors, the Important-Satisfaction Analysis(ISA) was applied as a mean of complement since the 1970s. This study analyzed the difference between visitor satisfaction and the importance of the main management strategy targeting visitors to Sun-cheon Bay Ecological Park on weekdays and weekends. Results show that Sun-cheon Bay Ecological Park and the city government have paid a lot of attention and invested a lot of money, but efficiency of publicity didn't come up to their afford. Therefore, we should prepare information facilities, public education facilities and human power. Also needed are visitors' temporal-spacial control to set specific programs and a guide for information education control. It means visitors' company forms change depends on weekday and weekend. In addition, a breeding space for birds should be built for observation, education and exhibition to help meet visitor expectations. Visitors' positive satisfaction might be provided in establishing strategy as a very important measure in limited area. In conclusion, this study might be provided as preliminary data when the management strategy and related guidelines are established through the management priority of coastal regions where importance and satisfaction conflict.

• Journal of Astronomy and Space Sciences
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• v.24 no.4
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• pp.367-378
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• 2007

We present a software which we developed for the multi-purpose CCD camera. This software can be used on the all 3 types of CCD - KAF-0401E ($768{\times}512$), KAF-1602E ($1536{\times}1024$), KAF-3200E ($2184{\times}1472$) made in KODAK Co.. For the efficient CCD camera control, the software is operated with two independent processes of the CCD control program and the temperature/shutter operation program. This software is designed to fully automatic operation as well as manually operation under LINUX system, and is controled by LINUX user signal procedure. We plan to use this software for all sky survey system and also night sky monitoring and sky observation. As our results, the read-out time of each CCD are about 15sec, 64sec, 134sec for KAF-0401E, KAF-1602E, KAF-3200E., because these time are limited by the data transmission speed of parallel port. For larger format CCD, the data transmission is required more high speed. we are considering this control software to one using USB port for high speed data transmission.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.419-427
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• 2020

This study was undertaken to address the difficulties and inconveniences of an electric wheelchair. We focused on improving usability of initially completed products by augmenting the prototypes designed in the previous study. For evaluation of usability, 10 elderly women aged over 65 years, capable of movements and physical activities in daily life, were enrolled as subjects. The experimental method included a subjective satisfaction questionnaire evaluation of the elderly women using the target product, and the observation evaluation was achieved using video recording data, etc. Usability evaluation revealed that the elevating sector requires improvement of intuition through separation of the elevating control panel and the driving control panel. Improvements in the driving sector include corrections of the front wheel mechanism or driving control algorithm, UI, and sudden stop system. Transferring section assessment revealed a necessity to secure structures and add structures that support power. We believe that based on the inconveniences and improvements presented in the usability evaluation, appending the existing prototype with complementary products will improve the quality of life of elderly women with limited mobility.

• Herbal Formula Science
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• v.18 no.1
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• pp.79-85
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• 2010

Objectives : This study was conducted to evaluate the acute toxicity and safety of Gumiganghwal-tang (Jiuweiqianghou-tang) in Sprague-Dawley rats though the current regulatory guideline. Methods : The preliminary study showed that the single oral administration of Gumiganghwal-tang(Jiuweiqianghou-tang) did not induce any toxic effect at a dose level of 2000 mg/kg. Based on the results, 2000 mg/kg was selected as the limited dose. In this study, 10 rats of each sex were randomly assigned to two groups of 5 rats each and were administrated singly by gavage at dose levels of 0 and 2000 mg/kg. Mortalities, clinical signs, and body weight changes were monitored for the 15-day period following administration. At the end of observation period, all animals were sacrificed and complete gross postmortem examinations were performed. Results : Throughout the study period, no treatment-related deaths were observed. There were no adverse effects on clinical signs, body weight, and gross findings at all treatment groups. Conclusions : These results showed that the single oral adminstration of Gumiganghwal-tang(Jiuweiqianghou-tang) did not cause any toxic effect at the dose levels of 2000 mg/kg in rats. In conclusion, the $LD_{50}$ of Gumiganghwal-tang (Jiuweiqianghou-tang) was considered to be over 2000 mg/kg body for both sexes.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.3
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• pp.264-274
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• 2013

This study investigates long-term trends and characteristics of aerosol light scattering coefficient at Seoul and Baengnyeongdo in order to understand aerosol optical and radiative properties around Korea. The analysis period is limited to one year of 2011. First, the aerosol scattering coefficients (${\sigma}_{sp}$) of both sites show strong linear dependence on the $PM_{2.5}$ mass concentrations with significant correlations between both. Further, correlations and sensitivity between ${\sigma}_{sp}$ and $PM_{2.5}$ increase with relative humidity, implying both relationships are strongly dependent upon moisture amounts in the atmosphere. This study applied 3-step careful quality control procedures to the analysis of ${\sigma}_{sp}$ for the insurance of data confidence. For the relationship analysis of extinction coefficients (${\sigma}_{ext}$) to visibility and aerosol optical depth, ${\sigma}_{sp}$ observed at 3 p.m. have been used with help of aerosol absorption coefficients (${\sigma}_{ap}$) in order to remove its dependence upon relative humidity, and also those of rainy period have been excluded. As expected, ${\sigma}_{ext}$ estimated are inversely proportional to visibility observation by eye. Finally, aerosol extinction coefficients have been vertically integrated with an assumption of nearly well-mixed within an e-folding height to determine aerosol optical depth, and compared with those retrieved from sunphotometer. The results show a reasonable agreement in spite of an inherent difference of each definition. We expect these findings would help to eventually understand aerosol radiative forcing and its effect on the regional climate change around Korea.

• The Journal of the Korea Contents Association
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• v.16 no.10
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• pp.503-513
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• 2016

Innovator and Early Adopter are main clients of smart phone until now, but the silver generation enjoying price stability and the Internet emerges, so a strategy of the importance, systematic classification, and focus of a neglected class is needed. It is necessary to analyze UI that can departmentalize not a neglected class limited to the silver generation but potential users who can be voluntarily users and can secure them. To secure them, the researcher analyzes how Windows, Icons, Mouse Pull-Down-Menus(WIMP) of UI has been applied in the process that skeuomorphism UI of iPhone, Metro UI of MS, and Material UI of Google change. As a result of an analysis, skeuomorphism is not entirely new and has secured potential users slowly with a method to compensate and improve a part that users disregard. As a concept of touch UI, Metro UI considered potential users from the beginning but did not secure them with new and epoch-making UI. However, Material UI of Google compensates the weaknesses of skeuomorphism UI and Metro UI and emphasizes cost-effectiveness, so has developed into UI that can secure final consumers of potential users. Therefore, to secure potential users, it should make users themselves understand why they should use smart phone, and it should approach with more organized studies on UI through feedback of observation and direct talks.

• Journal of the Korean Society for information Management
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• v.35 no.2
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• pp.89-114
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• 2018

Research on changes in research trends in academic disciplines is a method that enables observation of not only the detailed research subject and structure of the field but also the state of change in the flow of time. Therefore, in this study, in order to observe the changes of research trend in library and information science field in Korea, co-word analysis was conducted with Korean author keywords from three types of journals which were listed in the Korea Citation Index(KCI) and have top citation impact factor were selected. For the time series analysis, the 15-year research period was accumulated in 5-years units, and divided into 2003~2007, 2003~2012, and 2003~2017. The keywords which limited to the frequency of appearance 10 or more, respectively, were analyzed and visualized. As a result of the analysis, during the period from 2003 to 2007, the intellectual structure composed with 25 keywords and 8 areas was confirmed, and during the period from 2003 to 2012, the structure composed by 3 areas 17 sub-areas with 76 keywords was confirmed. Also, the intellectual structure during the period from 2003 to 2017 was crowded into 6 areas 32 consisting of a total of 132 keywords. As a result of comprehensive period analysis, in the field of library and information science in Korea, over the past 15 years, new keywords have been added for each period, and detailed topics have also been subdivided and gradually segmented and expanded.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.688-698
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• 2017

This study was conducted to identify the conceptual definitions and attributes of fatigue in hemodialysis patients based on the Hybrid Model of concept development. The Hybrid Model was used to investigate the main attributes and indicators of the concept by applying three stages. After a literature review, data were collected through observation and interviews including qualitative research in the field work stage. The participants included 10 patients in hemodialysis center of two hospitals in Gwang-ju, Korea. The attributes of fatigue concept in the hemodialysis patients were divided into four dimensions, physical activity, affective mood, social role, and cognitive reflection. The definition of fatigue by hemodialysis patients was defined as 'subjective feeling usually experienced in four dimensions during the process to recognize and adjust energy deficiency and limited functions caused by uremia and repeated hemodialysis for chronic renal failure'. Considering the dimensions and attributes derived from this study, it may be possible to develop an effective intervention program for fatigue in hemodialysis patients.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.7
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• pp.706-713
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• 2010

The research seeks to find the optimal conditions for sonodegradation of naphthalene and phenol as exemplary organic pollutants to be subjected to ultrasound in varying frequencies (28 kHz, 580 kHz, and 1,000 kHz) and in the presence of different kinds of additive (T$TiO_2$, $H_2O_2$, $FeSO_4$, Zeolite, and Cu). In cases of both naphthalene and phenol, 580 kHz of ultrasound has proven to be the most effective among others at sonodegradation. Based on the observation that OH radicals are also produced in maximum under exposure of 580 kHz of ultrasound, we concluded that this frequency of ultrasound creates hospitable condition for the combined process of degradation by pyrolysis and oxidization. $FeSO_4's$ degradation rate and k1 value have increased by approximately 1.8 times compared with the results of the solutions without any additives. This seems to be the result of ultrasound reaction which, accompanied by Fenton's reaction, increased the oxidative degradation and the production of OH radicals. However, application of ultrasound and Fenton's reaction is limited to the batch type conditions, as its use in continuous system can cause loss of iron or decay of the cistern, thereby creating additional pollutants. When the additive is replaced with $TiO_2$, on the contrary, the rate of sonodegradation has increased up to 20% compared to when there was no additive. We therefore conclude that $TiO_2$ could prove to be an effective additive for ultrasound degradation in continuous treatment system.