• Journal of Digital Convergence
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• v.11 no.7
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• pp.225-235
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• 2013

The purpose of this study is to investigate the Expected factors on the quality of life and its degree of elders in urban regions. Survey was conducted among 300 elders age of over 65, who attended four schools for elders at Busan metropolitan city in the month of October 2 to October 25, 2012 and data were collected 245 samples. Data analysed by using correlation analysis and multi-regression analysis to recognize the degree of the quality of life of elders and the result showed the expected factors on the quality of life and its major were as follows: First, average score of the quality of life of urban elders was 3.17 (5 scores of scale) and it indicated the medium result; Second, between sub-areas of the quality of life of subjects, significant positive relation was shown among every area excluding depression area;Third, the factors mostly influencing on the quality of life are mental health, social relation, and physical relation in order and it showed a significant level (p<0.001). The study revealed the symptoms of depression which reltaed to mental health, it indicated as a major factor to the quality of life, this study suggest there is requirement of nursing intervention and the application of health program to reduce the depression.

• Journal of Korea Water Resources Association
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• v.48 no.6
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• pp.425-438
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• 2015

The objective of this study was to evaluate simulation of agricultural water supply considering yearly variation of irrigation efficiency. The water supply data of the Idong reservoir from 2001 through 2009 was collected and used for this study. Total 6 parameters including irrigation efficiency (Es), drainage outlet height, and infiltration, were used for sensitivity analysis, calibration, and validation. Among the parameters, the Es appeared to be the most sensitivity parameter. The Es was calibrated on a yearly basis considering sensitivity and time-varying characteristic, while other parameters were set to fixed values. The statistics of percent bias (PBLAS), Nash-Sutcliffe efficiency (NSE), and root means square error to the standard deviation of measured data (RSR) for a monthly step were 2.7%, 0.93, and 0.26 for the calibration, and 3.9%, 0.89, and 0.32 for the validation, correspondently. The results showed a good agreement with the observations. This implies that the modeling only with appropriate parameter values, apart from modeling approaches, can simulate the real supply operation reasonably well. However, the simulations with uncalibrated parameters from previous studies produced poor results. Thus, it is important to use calibrated values, and especially, we suggest the Es's yearly calibration for simulating agricultural water supply.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.10
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• pp.523-532
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• 2003

Video on Demand(VOD) services cause high resource consumption in a video seuer, because multimedia are characterized by continuous playback, a high bandwidth requirement, and long playback duration. Patching has been proposed to save the network I/O bandwidth of a video server. To achieve true VOD, patching uses multicasting to share video streams, thereby providing immediate VOD services to users without any service latency. A communication channel is used to either multicast the entire video as a regular channel or multicast only the leading portion of a video as a Patching channel. This paper Proposes a buffering patching technique that divides regular channels, as used in patching, into sub-regular channels and regular channels to shorten the holding time of the channels. In the proposed technique, the last portion of video data, corresponding to the size of the buffering window, is not transferred by sub-regular channels, but rather downloaded and buffered in the user buffer from the latest regular channel. When simulations were performed to compare the performance of the proposed technique with that of conventional patching, the results indicated that the proposed technique was superior in terms of the defection rate, average service latency, and fairness, although the amount of video data buffered at each user station was higher than that with patching.

• Journal of KIISE:Software and Applications
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• v.33 no.7
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• pp.605-614
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• 2006

The success of a software development project can be determined by the use of QCD. And as a software's size and complexity increase, the importance of early quality assurance rises. Therefore, more effort should be given to prevention, as opposed to correction. In order to provide a framework for the prevention of defects, defect detection activities such as peer review and testing, along with analysis of previous defects, is required. This entails a systematization and use of quality data from previous development efforts. FMEA, which is utilized for system safety assurance, can be applied as a means of software defect prevention. SW-FMEA (Software Failure Mode Effect Analysis) attempts to prevent defects by predicting likely defects. Presently, it has been applied to requirement analysis and design. SW-FMEA utilizes measured data from development activities, and can be used for defect prevention on both the development and management sides, for example, in planning, analysis, design, peer reviews, testing, risk management, and so forth. This research discusses about related methodology and proposes defect prevention model based on SW-FMEA. Proposed model is extended SW-FMEA that focuses on system analysis and design. The model not only supports verification and validation effectively, but is useful for reducing defect detection.

• Korean Journal of Remote Sensing
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• v.23 no.4
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• pp.297-309
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• 2007

The first Korean geostationary weather satellite, Communications, Oceanography and Meteorology Satellite (COMS) will be launched in 2008. The ground station for COMS needs to perform geometric correction to improve accuracy of satellite image data and to broadcast geometrically corrected images to users within 30 minutes after image acquisition. For such a requirement, we developed automated and fast geometric correction techniques. For this, we generated control points automatically by matching images against coastline data and by applying a robust estimation called RANSAC. We used GSHHS (Global Self-consistent Hierarchical High-resolution Shoreline) shoreline database to construct 211 landmark chips. We detected clouds within the images and applied matching to cloud-free sub images. When matching visible channels, we selected sub images located in day-time. We tested the algorithm with GOES-9 images. Control points were generated by matching channel 1 and channel 2 images of GOES against the 211 landmark chips. The RANSAC correctly removed outliers from being selected as control points. The accuracy of sensor models established using the automated control points were in the range of $1{\sim}2$ pixels. Geometric correction was performed and the performance was visually inspected by projecting coastline onto the geometrically corrected images. The total processing time for matching, RANSAC and geometric correction was around 4 minutes.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.4
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• pp.731-751
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• 2021

The Internet of Things is a huge group of devices communicating each other and the interconnection of objects in the network is a basic requirement. Choosing a reliable device is critical because malicious devices can compromise networks and services. However, it is difficult to create a trust management model due to the mobility and resource constraints of IoT devices. For the centralized approach, there are issues of single point of failure and resource expansion and for the distributed approach, it allows to expand network without additional equipment by interconnecting each other, but it has limitations in data exchange and storage with limited resources and is difficult to ensure consistency. Recently, trust management models using fog nodes and blockchain have been proposed. However, blockchain has problems of low throughput and delay. Therefore, in this paper, a trust management model for selecting reliable devices in a fog-based IoT environment is proposed by applying IOTA, a blockchain technology for the Internet of Things. In this model, Directed Acyclic Graph-based ledger structure manages trust data without falsification and improves the low throughput and scalability problems of blockchain.

• Korean Journal of Construction Engineering and Management
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• v.20 no.4
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• pp.104-113
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• 2019

Construction dispute about Extension of Time are complexly intertwined with various issues. The duration delay analysis defines the impact the issue has on the duration variation. And The international court and the arbitrator use the results of the analysis as a basis for reasonable duration judging. However, most of the domestic Construction sites have not established a business process for Extension of Time litigation. Therefore, Analysis data are collected after the occurrence of the dispute, there is not enough basic data of analysis almost. This study sought to improve the management efficiency by organizing information requirement for delay analysis and suggesting a reasonable business process. As a result of applying the proposed process to actual construction duration extension disputes, about 33% of practitioners, 46% of contractors, and 48% of legal advisors were satisfied with the process application site And Matrix validation was 91% identical. This study suggests that it is possible to increase the efficiency of the construction duration analysis work used as a basis in the construction dispute. Finally, the Computer based system design for this process should continue in the future.

• The Journal of the Convergence on Culture Technology
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• v.5 no.2
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• pp.23-30
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• 2019

The purpose of this study was to examine job stress, job satisfaction, and turnover intention of the nurses who work at the comprehensive nursing service units in two academic medical institutions that provide healthcare service at the tertiary care level in Korea. A descriptive study was conducted with the nurses by using self-reported questionnaires. We used descriptive statistics to summarize the data and Mann-Whitney U test for group comparison. The mean scores of job stress, job satisfaction, and turnover intention were $89.17{\pm}12.56$, $107.25{\pm}6.85$, $37.19{\pm}4.86$, respectively. Nurses with religion showed more job stress than those without. Nurses with their age below 30 years old had significantly less job satisfaction than those older than 30 years old. Monthly income was significantly associated with turnover intention in our data. The top three sub-category of the job stress were conflict with physicians, patients and their caregivers, and conflicts with others; and those of the job satisfaction were pay and promotion and task requirement. Job stress, job satisfaction, and turnover intention were significantly correlated. In order to reduce turnover intention of nursing professionals in the comprehensive nursing service, job stress related to issues on relationships with patients, their family, health care providers need to be taken into consideration. Policy and administrative support are needed to improve their work environment.

• Journal of Internet Computing and Services
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• v.23 no.1
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• pp.49-68
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• 2022

The operation system of a shipping company is still maintaining the mainframe based terminal access environment or the client/server based environment. Nowadays shipping companies that try to migrate it into a web-based environment are increasing. However, in the transition, if the design is processed by the old configuration and knowledge without considering the characteristics of the web-based environment and shipping business, various security vulnerabilities will be revealed at the actual system operation stage, and system maintenance costs to fix them will increase significantly. Therefore, in the transition to a web-based environment, a security design must be carried out from the design stage to ensure system safety and to reduce security-related maintenance costs in the future. This paper examines the characteristics of various threat modeling techniques, selects suitable modeling technique for the operation system of a shipping company, applies data flow diagram and STRIDE threat modeling technique to shipping business, derives possible security threats from each component of the data flow diagram in the attacker's point of view, validates the derived threats by mapping them with attack library items, represents the attack tree having various attack scenarios that attackers can attempt to achieve their final goals, organizes into the checklist that has security check items, associated threats and security requirements, and finally presents 23 security requirements that can respond to threats. Unlike the existing general security requirements, the security requirements presented in this paper reflect the characteristics of shipping business because they are derived by analyzing the actual business of a shipping company and applying threat modeling technique. Therefore, I think that the presented security requirements will be of great help in the security design of shipping companies that are trying to proceed with the transition to a web-based environment in the future.

• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.3
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• pp.190-200
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• 2022

In this study, the island's land-use and land-cover change (LULCC) is analyzed in South Korea using remotely sensed land cover data(Globeland 30) acquired from 2000 to 2020 to meet the requirement of providing practical information for forest management. Analysis of LULCC between the 2000 and 2020 images revealed that changes to agricultural land were the most common type of change (7.6% of pixels), followed by changes to the forest (5.7%). The islands forests maintain 157,246 ha (42.2% of the total island area). Land cover types that changed to the forest from grasslands were 262 islands, while reverse cases have occurred on 421 islands. These 683 islands have a possibility of transition and disturbance. The artificial land class was newly calculated in 22 islands. The forests, which account for 42.2% of the 22 island area, turned into grassland, and 27.8% of agricultural land and grassland turned into forests. The development of artificial land often affects developed areas and surrounding areas, resulting in deforestation, management of agriculture, and landscaping. This study can provide insights concerning the fundamental data for assessing ecological functions and constructing forest management plans in islands ecosystems.