• KIISE Transactions on Computing Practices
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• v.22 no.5
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• pp.209-217
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• 2016

As smartphone usage increases, the number of consumers who refer to review data of e-commercial products using web sites and SNS is also explosively multiplying. However, reading review data using traditional websites and SNS is time consuming. Also, it is impossible for consumers to read all the reviews. Therefore, a system that collects review data of products and conducts sentiment word analysis of the review is required to provide useful information. The majority of systems that provide such information inadequately reflect the properties of the product. In this study, we described a system that provides analysis and evaluation of e-commerce products through review sentiment words as reflected properties of the product. Furthermore, the system enables consumers to access processed information about reviews quickly and in visual format.

• The Journal of Bigdata
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• v.7 no.1
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• pp.193-212
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• 2022

The Bass Diffusion Model is one of the most successful models in marketing research, and management science in general. Since its publication in 1969, it has guided marketing research on diffusion. This paper illustrates the usage of the Bass diffusion model, using mobile cellular subscription diffusion as a context. We fit the bass diffusion model to three large developed markets, South Korea, Japan, and China, and the emerging markets of Vietnam, Thailand, Kazakhstan, and Mongolia. We estimate the parameters of the bass diffusion model using the nonlinear least square method. The diffusion of mobile cellular subscriptions does follow an S-curve in every case. After acquiring m, p, and q parameters we use k-Means Cluster Analysis for grouping countries into three groups. By clustering countries, we suggest that diffusion rates and patterns are similar, where countries with emerging markets can follow in the footsteps of countries with developed markets. The purpose was to predict the timing and the magnitude of the market maturity and to determine whether the data follow the typical diffusion curve of innovations from the Bass model.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.3
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• pp.459-464
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• 2023

The mobile house of this article is provided with stand-alone power system that uses photovoltaic energy and enables sensing and environmental monitoring. Excess power generated is stored in lithium batteries, which enable smooth operation of the mobile house even in environment in which solar energy cannot be used. The house has been designed that its systems can be operated continuously by diesel power generation even when photovoltaic energy cannot be generated due to long rainy season or heavy snow. BMS (batter management system) has been constructed for photovoltaic and power management, and monitors the charge/discharge and usage amount of photovoltaic energy. Various sensing data are recorded and transmitted automatically, and the design allows for wireless monitoring by means of computer and smartphone app. The container house proposed in this study enables efficient energy management by performing optimal energy operation in remote areas, parks, event venues, and construction sites where there is no system power source.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.10
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• pp.986-992
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• 2012

As the utilization of smart mobile devices such as smartphones increases, the desire to utilize such devices to control and monitor combat situations also arises. As smart mobile devices with various ICT get integrated with various weaponry system, a new phase of future warfare can be introduced. Moreover, smartphone-based real-time information technology for joint battle command system will be converged with surveillance control to become a leading example of convergence of cyber defense and information technology. Furthermore, mobile device security technology ideal for mobile wireless network environments can be applied to military robots. The following paper will give an overview of smart mobile device usage used for military purposes in battle command system, various security threats and the mobile device security technology to correspond to such security threats.

• The Journal of Society for e-Business Studies
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• v.16 no.3
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• pp.67-91
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• 2011

Smart phones play a significant part in the evolution IT industry. In domestic market, smart phones have grown rapidly. However, until today, precedent studies on smart phones, particularly about the reason why consumers use smart phones are uncommon. Thus, in this study we adopted IS continuance and habit theory to study smart phones' use behavior. The results reveal that perceived usefulness and perceived ease of use, satisfaction of smart phone usage, continuous use, and habit showed the causes and effects relationships. The results indicated that perceived usefulness and perceived ease of use had a positive effect on smart phone user satisfaction. Moreover, smart phone user satisfaction had a positive effect on the smart phone habits and explorative use. However, smart phone user satisfaction showed insignificant effect toward exploitive use. That is, satisfied users regularly use the smart phone but need to formulate habit of use, and then influence exploitive use. Habit showed a positive effect on both exploitive use and explorative use, Finally, we found that users are likely to pay more attention on new features of smart phones while they are using the devices.

• Convergence Security Journal
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• v.12 no.4
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• pp.9-15
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• 2012

In recently years, repackaged malwares are becoming increased rapidly in Android smartphones. The repackaging is a technique to disassemble an app in a market, modify its source code, and then re-assemble the code, so that it is commonly used to make malwares by inserting malicious code in an app. However, it is impossible to collect all the apps in many android markets including too many apps. To solve the problem, we propose RePAD (RePackaged App Detector) scheme that is composed of a client and a remote server. In the smartphone-side, the client extracts the information of an app with low CPU overhead when a user installs the app. The remote server analyzes the information to decide whether the app is repackaged or not. Thus, the scheme reduces the time and cost to decide whether apps are repackaged. For the experiments, the client and server are implemented as an app on Galaxy TAB and PC respectively. We indicated that seven pairs of apps among ones collected in official and unofficial market are repackaged. Furthermore, RePAD only increases the average of CPU overhead of 1.9% and the maximum memory usage of 3.5 MB in Galaxy TAB.

• Journal of Digital Convergence
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• v.15 no.8
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• pp.183-193
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• 2017

Digital accredited certificates issued under the Digital Signature Act provide essential functionalities for online service, so certificates are used for various services such as online banking, e-government. However, certificates can be stolen by hackers and users need to install separate software to use certificates. Recently FIDO, which aims to solve the problems of password-based authentication and the lack of interoperability between authentication methods, is used for biometric authentication and TrustZone, hardware-based secure environment, is used for safe smartphone usage. In this paper, the new service method is suggested which uses FIDO-based biometric authentication and stores certificates in TrustZone. This method can not only improve security and convenience but also be easily applied to the service because it uses built-in functionalities of new smartphones such as biometric sensors and TrustZone. It is expected that people can use certificates in a safe and convenient way with this method.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.209-216
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• 2024

Land shrimp farms can control the growth environment more stably than coastal ones, making them advantageous for high-quality, large-scale production. In order to maintain an optimal shrimp growth environment, various factors such as water circulation, maintaining appropriate water temperature, oxygen supply, and feed supply must be managed. In particular, failure to properly manage water quality can lead to the death of shrimp, making it difficult to have people stationed at the farm 24 hours a day to continuously manage them. In this paper, to solve this problem, we design an integrated monitoring system for land farms that can be operated with minimal manpower. The proposed design plan uses IoT technology to collect real-time images of land farms, pump status, water quality data, and energy usage and transmit them to the server. Through web interfaces and smartphone apps, administrators can check the status of the farm stored on the server anytime, anywhere in real time and take necessary measures. Therefore, it is possible to significantly reduce field work hours without the need for managers to reside in the farm.

• Convergence Security Journal
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• v.16 no.7
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• pp.167-172
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• 2016

The purpose of this study is to provide implications for preventing insider information leakages in public agencies for national security. First, the study examined the definitions and current usage of information security systems of public agencies were examined. Second, web-service base information leaks and malware-base information leaks were discussed and three major credit card companies' personal information leakage cases were analyzed. Based on the analysis, four solutions were provided. First, information leakages can be protected by using web filtering solutions based on the user, which make possible to limit frequencies of malware exposures. Second, vaccine programs and vaccine management system should be implemented to prevent information leakages by malware. Third, limit the use of portable devices within local networks to prevent information leakages and vaccines programs for malware should be regularly used. Forth, to prevent information leakages by smartphone malwares, data encryption application should be used to encrypt important information.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.1
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• pp.97-111
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• 2024

Developing countries and small local governments face financial constraints, limiting the adoption of their own bus information systems. However, despite poor social infrastructure and low income levels, developing countries have a high smartphone penetration rate, and the distribution and usage of online content and social media are widespread. Smartphones, equipped with GPS sensors, cameras, and other location-based information collection capabilities, can replace expensive on-site terminals. This study aims to replace expensive on-site terminals with smartphones, develop a center system based on cloud servers, and establish an extensible Open BIS (Bus Information System) service and platform that can be applied anywhere. The goal is to formulate a business model in the process.