• Journal of Digital Convergence
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• v.12 no.6
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• pp.277-287
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• 2014

In LBSNS(Location-based Social Network Service), users can share locations and communicate with others by using check-in data. The check-in data consists of POI name, category, coordinate and address of locations, nickname of users, evaluating grade of locations, related article/photo/video, and etc. If you analyze the check-in data from the location-based social network service in accordance with your situation, you can provide various customized services. Therefore, In this paper, we develop a location recommendation system based on LBSNS that can utilize the check-in data efficiently. This system analyzes the location category of the check-in data, determines the weighted value of it, and finds out the similarity between users by using the Pearson correlation coefficient. Also, it obtains the preference score of recommended locations by using the collaborated filtering algorithm and then, finds out the distance score by applying the Euclidean's algorithm to the recommended locations and the current users' locations. Finally, it recommends appropriate locations by applying the weighted value to the preference score and the distance score. In addition, this paper approved excellence of the proposed system throughout the experiment using real data.

• Journal of Digital Convergence
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• v.16 no.4
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• pp.299-306
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• 2018

This study is to measure traveling experience of bike riders whom going long distance trip. Bike paths and bike riding are crucial element for modern people's life style. At the same time, a bicycle trail is being developed by the National Bicycled-Oriented Chair Plan, which was established in 2009 by the National Bike Policy Master Plan. 13 million bike riders in Korea is keep on trying the long distance bike trip and its number is increasing every year. Accordingly, the Ministry of Public Administration and Security decides to promote the convenience of riders by developing bicycle app for long distance rider. The study attempted to assess usability of this app with 39 bike applications whom currently using the bike application. Afterwards, the researchers tests 11 hypotheses through in-depth interviews of six activated members. In sum, Bicycle travelers should be provided with bike trail guidance based on theme section skill, provided in-time speed distance related information, communicated with other bike riders, given tips for bike supplies and maintenance, and provided English language service. The study hopes to help find a customized service for bike travelers.

• Journal of Digital Convergence
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• v.15 no.6
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• pp.407-414
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• 2017

With an increase in urban crimes in various forms, this study is intended to analyze the effectiveness of the service design that presented a new model resolving crime risks through differentiated thinking paradigm and problem approaches. The empirical case addressed in this study is 'the project to create resident-driven safe community in Duryu-dong, Dalseo-gu, Deagu though service design'. This project is evaluated as having prepared a prevention-oriented local safety system through a preemptive and resident-centered process. The project was promoted as a 'natural monitoring capacity building program' for residents to prevent local crimes, a 'social role expansion program' for local safety, and 'crime prevention environment design', which provides comprehensive solutions for residents' safety. Here, designers act as exerts in designing a task-based platform that can be driven by residents rather than a visual environment improver, and reorganizing the local ecosystem by expanding the opportunities for residents to interact. This case identifies the role of service design as binding the solidarity of local residents beyond the improvement of the crime environment and giving them the potential capacity to maintain a safe living space in relation to a safety issues of community.

• Journal of Digital Convergence
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• v.16 no.3
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• pp.145-156
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• 2018

Unlike the past, when distributors distributed games through retail stores, they are now selling digital content, which is based on online distribution channels. This study analyzes the effects of eWOM (electronic Word of Mouth) on sales volume of game sold on Steam, an online digital content distribution channel. Recently, data mining techniques based on Big Data have been studied. In this study, emotion index of eWOM is derived by emotional analysis which is a text mining technique that can analyze the emotion of each review among factors of eWOM. Emotional analysis utilizes Naive Bayes and SVM classifier and calculates the emotion index through the SVM classifier with high accuracy. Regression analysis is performed on the dependent variable, sales variation, using the emotion index, the number of reviews of each game, the size of eWOM, and the user score of each game, which is a rating of eWOM. Regression analysis revealed that the size of the independent variable eWOM and the emotion index of the eWOM were influential on the dependent variable, sales variation. This study suggests the factors of eWOM that affect the sales volume when Korean game companies enter overseas markets based on steam.

• Journal of Digital Convergence
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• v.15 no.10
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• pp.399-404
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• 2017

If game images use colors improper for certain ages, the characteristics of games disappear, and the efficiency of image expression drops. thus a study in color is very important. Nevertheless, there is a lack of research on this subject. In this study, we investigated the difference of color of game images according to users. User group is divided into all users and users over 18 years old. Among the rank of games,10 each from games for all ages and games for non-teen-rated are selected, and the game-playing images are taken as snapshots to have 100 each images each, A total of 2000 images were extracted and the mean values of RGB and HSB of each game were obtained and independent sample t test was performed. The results showed that the RGB color values between the two users were significantly significant. In the future, it is expected that it will be helpful in color selection when developing psychotherapy games and emotional games using color psychology. Furthermore, we will use color image scales to express colors as adjectives, analyze colors in a variety of ways, and investigate the difference in color of game images in each country.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.3
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• pp.125-131
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• 2011

Water leak detection system is a system based on wireless sensor networks(WSNs) which detect a leak on water supply, localize the leak position and finally inform a water management center. A traditional leak detection method is to use experienced personnel who walk along a pipeline listening to the sound that is generated by the leaks and their effectiveness depend on the experience of the user. Also making more successful detection, it should be processed at middle of the night when people do not use water, as the result users have to operate the leak detection system at midnight. In this paper, we propose a new method for the water leak detection system based on the WSNs and describe it in detail. Leak detection devices which detect a leakage of water transmit and receive the result of water leak detection with each other by configuring WSNs to improve reliability of the detection result. Also, we analyzed the sound from water flowed in pipeline, proposed the pre-signal processing to separate a leakage sound from noisy sound. And lastly, It is especially important to make a time synchronization with water leak detection devices that are installed on the pipeline, we used 1PPS(1 Pulse Per Second) signal generated by GPS, therefore we could get a precise time synchronization. The proposed system set up in Namyangju and performances were evaluated.

• Journal of Environmental Health Sciences
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• v.43 no.3
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• pp.223-232
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• 2017

Objectives: In response to increased interest in the safety of children's products, a risk management system is being prepared through exposure assessment of hazardous chemicals. To estimate exposure levels, risk assessors are using deterministic and probabilistic approaches to statistical methodology and a commercialized Monte Carlo simulation based on tools (MCTool) to efficiently support calculation of the probability density functions. This study was conducted to analyze and discuss the usage patterns and problems associated with the results of these two approaches and MCTools used in the case of probabilistic approaches by reviewing research reports related to exposure assessment for children's products. Methods: We collected six research reports on exposure and risk assessment of children's products and summarized the deterministic results and corresponding underlying distributions for exposure dose and concentration results estimated through deterministic and probabilistic approaches. We focused on mechanisms and differences in the MCTools used for decision making with probabilistic distributions to validate the simulation adequacy in detail. Results: The estimation results of exposure dose and concentration from the deterministic approaches were 0.19-3.98 times higher than the results from the probabilistic approach. For the probabilistic approach, the use of lognormal, Student's T, and Weibull distributions had the highest frequency as underlying distributions of the input parameters. However, we could not examine the reasons for the selection of each distribution because of the absence of test-statistics. In addition, there were some cases estimating the discrete probability distribution model as the underlying distribution for continuous variables, such as weight. To find the cause of abnormal simulations, we applied two MCTools used for all reports and described the improper usage routes of MCTools. Conclusions: For transparent and realistic exposure assessment, it is necessary to 1) establish standardized guidelines for the proper use of the two statistical approaches, including notes by MCTool and 2) consider the development of a new software tool with proper configurations and features specialized for risk assessment. Such guidelines and software will make exposure assessment more user-friendly, consistent, and rapid in the future.

• Journal of The Korean Digital Architecture Interior Association
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• v.2 no.1
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• pp.9-15
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• 2002

As architectural forms tend to be large-scaled, high-storied and complicated, use of computer for processing design information has been generalized. However, CAD use in the process of developing architectural design has been neglected greatly in the educational field of architectural field due to the surging of recognition that it may limit the essential property of architectural design. It may be resulted from the limitation of CAD system, that is, it is because of tardy speed of application development for the related areas with the lack of simplicity and clarity of flexibility to be secured on the drawing and user interface. Recent CAD systems, however, overcome such a limitation, convert into object-based design from entity-based drawing, drafting and modeling for implementing design concept of architects and it connects with internet linked to superspeed information communication network and changes process and stream of architectural design. Therefore, this study deals with utility of object based CAD system with products of Autodesk Co. and consequently obtain the following conclusions. First, it expands architect's design areas by supporting cooperative design system based on model-based architectural design and internet. Second, it reduces consumption of personal and material resources and time in the process of drawing production for improving architectural design works. Third, it can reduce the frequent design changes by improving understanding of architectural space with visualization of immediate 3D information, escaping from traditional methods to deliver design information to building owner through 2D drawing or model and perspective drawing requiring much cost and time. Fourth, it keeps exactness without omission or duplication of design information and generate and renew information of all related drawings on a drawing. Fifth, it is possible to change difficult and boring architectural design work into a pleasure owing to immediate modeling and drawing of design idea. In addition, digital drawing generated by using object-based CAD system can playa role of establishing Urban Information System to be used for protecting from building in disaster and urban disasters in connection with GIS numerical map and be used for reference of all kinds of information required fro post-management of buildings. However, what is more important is that surplus time from introduction of object-based CAD system should be used for consideration to be recognized as a good space and building built as a product of this project for comfort to urban people.

• Journal of Families and Better Life
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• v.25 no.3 s.87
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• pp.119-135
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• 2007

The purpose of this study is to find out the level of digital stress that people experience and to investigate the effects of socio-economic variables on that. To collect data, structured questionnaire was developed and 1,200 questionnaires were distributed through internet. There were 2 dimensions in this study to examine digital stress. First dimension was about the devices themselves: computers and the other digital goods. Second dimension was about the time digital stress occurring in consumers' decision-making process: purchasing and using. Based on Yeo&Kim(2004), sub-dimensions of purchasing and using aspects were chosen. 5 sub-dimensions in purchasing side were new technology, cost, variety of alternatives, warranty service, and informational problem 6 sub-dimensions in using field were mal(or impaired)-functioning. physical aspects, immaturity in use, pressure to use, addiction to use, and informational problem. As independent variables, sex, age, educational level, digitalization acceptability and computer usability were used. The overall level of digital stress was around the average point which was not as high as expected. Digital stress of purchasing was higher than that of using. First, in purchasing aspects, the level of digital stress was relatively high in cost, variety of alternatives and warranty service. Hence, clear communications with consumers about the distinctive aspects and cost of digital devices in market are needed. Secondly, in using side, mal-functioning and physical aspects were relatively more powerful stressors. In the other words, the more serious problems were not from the characteristics of individual consumers but from those of products. Producers should put their best efforts to reduce imperfection (defectiveness) and develop user-friendly digital devices. Also, users' individual efforts to overcome the problems that can be solved privately are necessary. Finally, it was discovered that sex and computer usability were very important variables on digital stress. To extend computer usability of consumers and get over digital illiteracy, it is essential to expand the paths to give chances for people to contact with computers and other digital goods. Still there are lots of people whore computer-illiterate or low-skilled at computers. In policies or educational programs made by government, communities, or schools, more attention should be paid to the digitally vulnerable groups.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.1
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• pp.68-78
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• 2013

In this paper, we propose an early spectrum sensing(ESS) as an advance preparation for radio-access trial, which enables multi-mode terminals to access the most appropriate radio-access system in a cloud-conceptual base station system where multiple radio access technologies(RATs) coexist. Prior to a random access to one of RATs, a multi-mode terminal conducts a spectrum sensing over entire frequency bands of whole RATs, then select the RAT with the lowest sensing power, that is likely to have the most available spectrum. Thus, an access failure caused by that the selected RAT has no available radio spectrum could be avoidable in advance. In computer simulation, we consider as various RATs as possible. First, circuit and packet systems are taken into consideration. In addition, the packet systems are classified according to the feasibility of carrier aggregation(CA). In case of terminal, three modes are considered with circuit-only, packet-only, and multi-mode. Subsequently, packet traffic is classified into real-time and non-real-time traffic with three different tolerable delay levels. The simulation includes a call process starting with a call generation and ending up with a resource allocation reflecting individual user's QoS requirements and evaluates the proposed scheme in terms of the successful access probability, system access time, system balancing factor and packet loss probability.