• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.1
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• pp.139-143
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• 2019

Measurement of flow rate is required in various fields. Water meters are often used at home, and flow meters are used in water and sewage plants, petrochemical industries and so on.. A system is needed to monitor the flow rate in real time and notify immediately when flow rate is abnormal. Recently, with the development of the IoT it is possible to construct such devices at low cost. WeMos can be programmed with Arduino IDE as a mini wifii IoT module. The flow sensor can output a digital pulse proportional to the flow rate. In this paper, we developed the flow monitoring and warning system using WeMos and IoT technology. When the system operates, it calculates the flow rate, sends the value as JSON format to the server, monitors the flow rate as graph from the remote with the smartphone. We also implement the system to promptly send alert message to the smart phone using Pushbullet when the flow rate is abnormal.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.41-47
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• 2023

This study was conducted to determine the effect of an exercise program applied to prevent musculoskeletal changes that occur due to aging on pain, muscle strength, balance ability, and falling efficacy in elderly women. An exercise program including quadriceps setting exercise, bridge exercise, resistance band exercise, and foam roller exercise was applied to elderly women aged 65 years or older once a week for 8 weeks. A visual analog scale was used to evaluate pain, muscle strength was evaluated using a digital muscle strength meter, balance ability was measured using the Berg balance scale, and fear of falling was evaluated using the fall efficacy scale. As a result of the study, compared to before the experiment, pain in the lower back and knee area was significantly reduced, the strength of the quadriceps femoris and gluteus maximus was significantly increased, and balance ability and falling efficacy were significantly improved. In conclusion, application of a program that includes various exercise methods has a positive effect on the physical activity of elderly women by strengthening the musculoskeletal system. Additionally, in order to prevent physical changes due to aging, an exercise program that includes various exercise methods that can strengthen the musculoskeletal system should be applied.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.11 no.2
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• pp.37-48
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• 2006

HF radar-derived current data obtained in 2002 and 2004 are analyzed to examine the effects of the completion of the Saemangeum 4th tidal dyke in June 2003, connecting Gogunsan-Gundo and Bieung-Do, on the coastal surface $M_2$ current pattern. Comparison between the currents by HF radar and current meter mooring showed good agreements. Counterclockwise rotation of the $M_2$ current in the observed area did not change with the dyke construction. Strong westward ebb jet from the gap of the dyke was observed in 2002 but disappeared in 2004. The complete closing of the dyke gap caused the current speed increase around the mouth of the Kem River estuary, decrease around Gogunsan-Gundo and the dyke, the changes in the direction of maximum current to north-ward from eastward and the delay of the maximum flood current occurrence around Gogunsan-Gundo and the dyke. Around Yeon-Do, the maximum flood current directed more clockwise and occurred rather earlier. These changes of the $M_2$ current ellipse characteristics imply that the effects of the dyke construction reached the area connecting Mal-Do and Yeun-Do.

• Journal of the Korean Wood Science and Technology
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• v.37 no.1
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• pp.37-47
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• 2009

For the inspection of wood, machine vision is the most common automated inspection method used at present. It is required to sort wood products by grade and to locate surface defects prior to cut-up. Many different sensing methods have been applied to inspection of wood including optical, ultrasonic, X-ray sensing in the wood industry. Nowadays the scanning system mainly employs CCD line-scan camera to meet the needs of accurate detection of lumber defects and real-time image processing. But this system needs exact feeding system and low deviation of lumber thickness. In this study low cost CCD area sensor was used for the development of image processing system for lumber being fed. When domestic red pine being fed on the conveyer belt, lumber images of irregular term of captured area were acquired because belt conveyor slipped between belt and roller. To overcome incorrect image merging by the unstable feeding speed of belt conveyor, it was applied template matching algorithm which was a measure of the similarity between the pattern of current image and the next one. Feeding the lumber over 13.8 m/min, general area sensor generates unreadable image pattern by the motion blur. The red channel of RGB filter showed a good performance for removing background of the green conveyor belt from merged image. Threshold value reduction method that was a image-based thresholding algorithm performed well for knot detection.

• Journal of the Korean Society for Railway
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• v.19 no.3
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• pp.280-287
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• 2016

In railway tunnels, dust is generated when trains run due to the contact between the wheels and the rails. The generated dust is suspended due to the train-induced airflow, with some of it deposited due to gravitational sedimentation. In this study, the diurnal variation of the dust concentration was investigated in a railway tunnel. A single lane of a tunnel was selected in which to observe more easily the dust concentration due to the passing of a train. Four particle-measuring instruments were utilized to detect dust ranging from 5nm to $20{\mu}m$. To synchronize the train passing time at the measuring location, a three-dimensional ultrasonic anemometer and a video camera were used. It was found that the dust concentration was significantly increased from $50{\mu}g/m^3$ to $150{\mu}g/m^3$ due to the train. Particularly, the dust concentration was greatly increased to more than $250{\mu}g/m^3$ during the morning rush-hour times.

• Journal of Wetlands Research
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• v.23 no.4
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• pp.296-306
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• 2021

Elasticity is a statistical technique that interprets the changing pattern of another variable according to a change in one variable as a quantitative numerical value and provides more information than correlation analysis and is widely used in climate change research. In this study the elasticity was calculated and sensitivity analysis was performed using air temperature and water quality data of the major tributaries of the Nakdong River. In addition the confidence interval for the elasticity was calculated using the T-Test and the validity of the elasticity was examined. The strength of elasticity shows high strength in the order of summer>fall>spring>winter and the direction shows regional characteristics with both negative and positive elasticity. After performing hierarchical cluster analysis on monthly observation data they were classified into 5 clusters and the characteristics of each cluster were visually analyzed using a parallel coordinate graph. The direction and intensity of the air temperature elasticity show regional characteristics due to the relatively high population density and complex influencing factors such as sewage treatment plants, small-scale livestock houses and agricultural activities. In the case of TP it shows great regional variability according to the circulation of nutrients in the ecosystem caused by algae growth and death according to temperature changes. Since the air temperature elasticity of the major tributaries of the Nakdong River is over weak and is valid at the significance level of 5%, it was analyzed that there is a change in water quality according to the air temperature change.

• The Korean Journal of Applied Statistics
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• v.33 no.6
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• pp.777-789
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• 2020

COVID-19 has been rapidly spread world wide since late December 2019. In this paper, our interest is to estimate distribution of incubation time defined as period between infection of virus and the onset. Due to the limit of accessibility and asymptomatic feature of COVID-19 virus, the exact infection and onset time are not always observable. For estimation of incubation time, interval censoring technique is implemented. Furthermore, a competing risk model is applied to estimate the case fatality and cure fraction. Based on the result, the mean incubation time is about 5.4 days and the fatality rate is higher for older and male patient and the cure rate is higher at younger,female and asymptomatic patient.

• Korean Security Journal
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• no.18
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• pp.169-190
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• 2009

Today, the rapid advance of scientific technologies has brought about fundamental changes to the types and levels of terrorism while the war against the world more than one thousand small and big terrorists and crime organizations has already begun. A method highly likely to be employed by terrorist groups that are using 21st Century state of the art technology is cyber terrorism. In many instances, things that you could only imagine in reality could be made possible in the cyber space. An easy example would be to randomly alter a letter in the blood type of a terrorism subject in the health care data system, which could inflict harm to subjects and impact the overturning of the opponent's system or regime. The CIH Virus Crisis which occurred on April 26, 1999 had significant implications in various aspects. A virus program made of just a few lines by Taiwanese college students without any specific objective ended up spreading widely throughout the Internet, causing damage to 30,000 PCs in Korea and over 2 billion won in monetary damages in repairs and data recovery. Despite of such risks of cyber terrorism, a great number of Korean sites are employing loose security measures. In fact, there are many cases where a company with millions of subscribers has very slackened security systems. A nationwide preparation for cyber terrorism is called for. In this context, this research will analyze the current status of Korea's cyber security systems and its laws from a policy perspective, and move on to propose improvement strategies. This research suggests the following solutions. First, the National Cyber Security Management Act should be passed to have its effectiveness as the national cyber security management regulation. With the Act's establishment, a more efficient and proactive response to cyber security management will be made possible within a nationwide cyber security framework, and define its relationship with other related laws. The newly passed National Cyber Security Management Act will eliminate inefficiencies that are caused by functional redundancies dispersed across individual sectors in current legislation. Second, to ensure efficient nationwide cyber security management, national cyber security standards and models should be proposed; while at the same time a national cyber security management organizational structure should be established to implement national cyber security policies at each government-agencies and social-components. The National Cyber Security Center must serve as the comprehensive collection, analysis and processing point for national cyber crisis related information, oversee each government agency, and build collaborative relations with the private sector. Also, national and comprehensive response system in which both the private and public sectors participate should be set up, for advance detection and prevention of cyber crisis risks and for a consolidated and timely response using national resources in times of crisis.

• Journal of the Korean Geographical Society
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• v.39 no.4
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• pp.643-664
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• 2004

This study aims to review what geographers have contributed to GIS industries and national needs. To-be-geographers and geographers are expected to meet the gap between what we have teamed in school and what we have to do after graduation. The characteristics of GIS industry in the 1990 are summarized with approximate evaluation of the contribution of geographers in each stage. Author introduced the requirement for the licenses of geomatics and geospatial engineering experts and the other licenses, which are important to get a job in GIS industry from 2003 to 2004. A set of questionnaire on the user's requirements was given to GIS people in private companies and public GIS research centers and analyzed. Author found that they put an emphasis on hands-on experiences and programming skills. no advantages or geography such as capability or integration and inter-disciplinary collaboration were not appreciated. The prospects for the GIS tend to be positive but the reflectance of the prospect was not accompanied by at the same degree of preference for geography. Most government strategies for the next ten years' GIS focus on new-growth leading industries. SWOT(strength, weakness, opportunity, threat) analysis of geography for GIS industry will give some directions such as telematics, regional marketing strategies with web-based GIS technology, location based service. That means intra-disciplinary study in geography will evoke the potentiality of GIS, compared with interdisciplinary studies.