• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1307-1312
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• 2015

As smart-phones become popular, mobile data traffic has been dramatically increasing and intensive researches on the next-generation mobile communication network is in progress to meet the increasing demand for mobile data traffic. In particular, heterogeneous network (HetNet) is attracting much interest because it can significantly enhance the network capacity by increasing the spatial reuse with macro and small cells. In the HetNet, we have several problems such as load imbalance and interference because of the difference in transmit power between macro and small cells and cell range expansion (CRE) can mitigate the problems. In this paper, we propose a new cell selection scheme with adaptive cell range expansion bias (CREB) for ultra dense HetNet and we analyze the performance of the proposed scheme in terms of average cell transmission rate through system-level simulations and compare it with those of other schemes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.63-66
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• 2015

As smart-phones become popular, mobile data traffic has been dramatically increasing and intensive researches on the next-generation mobile communication network is in progress to meet the increasing demand for mobile data traffic. In particular, heterogeneous network (HetNet) is attracting much interest because it can significantly enhance the network capacity by increasing the spatial resue with macro and small cells. In the HetNet, we have several problems such as load imbalance and interference because of the difference in transmit power between macro and small cells and cell range expansion (CRE) can mitigate the problems. In this paper, we propose a new cell selection scheme with adaptive cell range expansion bias (CREB) for ultra dense HetNet and we analyze the performance of the proposed scheme in terms of average cell transmission rate through system-level simulations and compare it with those of other schemes.

• Journal of the Korean Society of School Health
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• v.29 no.3
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• pp.149-155
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• 2016

Purpose: The purpose of this study was to identify the influence of cell phone addiction on communication skills and the interpersonal relationship ability of adolescents. Methods: The researcher recruited 751 high school students to assess their general characteristics, communication skills, cell phone addiction and interpersonal relationship ability. Data were collected from June 30 to July 14 in 2014 using copies of a structured self report questionnaire. The collected data were analyzed with descriptive statistics, t-test, ANOVA, Pearson's correlation coefficient and linear multiple regression using the SPSS/WIN 21.0 IBM program. Results: Of the students, 3.5% reported they were addicted users, and 7.6% reported they were heavy users. Results from multiple regression analysis showed that cell phone addiction did not have any influence on communication skills of the adolescents. However, cell phone addiction mostly affected the interpersonal relationship ability of the adolescents (${\beta}=.24$, p<.001). Poor school performance (${\beta}=.17$, p<.001) and low socioeconomic status (${\beta}=.12$, p<.05) were also related to the interpersonal skills of the adolescents. These variables explained 8.3% of the variance in the interpersonal skills of the adolescents. Conclusion: These results suggest that cell phone addiction has a negative influence on the development of the interpersonal relationship ability of adolescents. The findings of this study are expected to provide basic data about the influence of cell phone addiction on the interpersonal relationship ability of adolescents. Therefore, cell phone addiction treatment programs for adolescents need to include contents related to interpersonal relationship ability.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.252-256
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• 2001

The rapid development of communication equipment and information processing technology has led to a constant improvement in cordless communication. Lithium ion batteries used in cellular phones and laptop computers, in particular, have been in the forefront of the above revolution. These batteries use high value added raw materials and have a high and stable energy output and are increasingly coming into common use. The development of the material for the negative terminal has led to an improvement in the quality and efficiency of the batteries, whereas a reduction in the cost of the battery by researching new materials for the positive anode has become a research theme by itself. These long life batteries, it is being increasingly realized, can have value added to them by recycling. Research is increasingly being done on recycling the aluminum case and the load casing for the negative diode. This paper aims to introduce the current situation of recycling of lithium ion batteries. 1. Introduction 2. Various types of batteries and the situation of their recycling and the facts regarding recycling. 3. Example of cobalt recycling from waste Lithium ion secondary cell. 3-1) Flow Chart of Lithium ion battery recycling 3-2) Materials that make a lithium ion secondary cell. 3-3) Coarse grinding of Lithium ion secondary cell, and stabilization of current discharge 3-4) Burning 3-5) Grinding 3-6) Magnetic Separation 3-7) Dry sieving 3-8) Dry Classifying 3-9) Content Ratio of recycled cobalt parts 3-10) Summary of the Line used for the recovery of Cobalt from waste Lithium ion battery. 4. Conclusion.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.57-63
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• 2021

The Cell Broadcast Service is a public service that delivers information on disaster situations to mobile phones. In Korea, where mobile phone penetration is high, disaster information delivery through Cell Broadcast Service has a higher preference than other information delivery methods. However, since it consists only of text messages, disaster information is not delivered normally to the information vulnerable class compared to the general public. To compensate for this, a disaster information delivery application using Cell Broadcast Service was proposed and research was conducted. If research like this paper continues and Cell Broadcast Service become a service that transmits various disaster-related information considering the information vulnerable at home and abroad, it will provide the effect of reducing damage to disasters through rapid and accurate response.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4593-4595
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• 2012

Introduction: Mobile learning enables users to interact with educational resources while in variable locations. Medical students in residency positions need to assimilate considerable knowledge besides their practical training and we therefore aimed to evaluate the impact of using short message service via cell phone as a learning tool in residents of Obstetrics and Gynecology in our hospital. Methods: We sent short messages including data about breast cancer to the cell phones of 25 residents of gynecology and obstetrics and asked them to study a well-designed booklet containing another set of information about the disease in the same period. The rate of learning derived from the two methods was compared by pre- and post-tests and self-satisfaction assessed by a relevant questionnaire at the end of the program. Results: The mobile learning method had a significantly better effect on learning and created more interest in the subject. Conclusion: Learning via receiving SMS can be an effective and appealing method of knowledge acquisition in higher levels of education.

• The Journal of Information Systems
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• v.13 no.2
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• pp.89-117
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• 2004

Mobile technologies and services have become one of the inevitable parts of people's lives and mobile businesses have also been widespread. Popular mobile internet services through cell phones have made people in the financial industry consider that 'mobile' is promising. Nevertheless, there have been little studies of mobile services in the financial industry and most of the studies have been concentrated on internet services. The main purpose of this study is to investigate on the determinants of intention to use mobile banking. To achieve the goal, based on the theoretical backgrounds of the Technology Acceptance Model(TAM). Survey questionnaires were distributed via post & email to 500 users who have been experiences with cell phone and have an account. Out of 291 responded questionnaires, 275 data sets were available for statistical analysis with SPSS 10.1. Research hypotheses are analyzed by LISREL 8.30. Factor analysis identified seven external factors : (1) convenience, (2) cost, (3) unusefulness, (4) riskiness, (5) personal innovativeness (6) users' self-efficacy (7) experience of mobile services. Results of this study show that convenience, unusefulness, riskiness, personal innovativeness and experience of mobile services have significant effects on intention to use mobile banking . Much of the previous researches have dealt with service provider only and have focused on mobile internet. In this regard, when it comes to a viewpoint that regards the mobile banking sector as a new sector of mobile businesses. This study may provide a guideline to activate of mobile banking acceptance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.218-223
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• 2008

Cell-phone becomes a necessary communication device in modern society. However, a paging signal by a sound transducer often acts as an unpleasant noise, thus necessitating a paging signal by a vibration motor. The conventional flat type vibration motor uses three-phase windings with three phase coils. In this article, a new design of a vibration motor using a V connection with two phase coils is presented, increasing mass productivity. For electromagnetic field analysis, due to the motor symmetry, two-dimensional modeling can be implemented for fast computation, and performance is predicted by the finite element method. The winding distribution angle turns out to be the most important design parameter for the elimination of dead points, and a new coil configuration is suggested which has no adverse effect on motor size and weight. Experimental tests of vibration confirm the validity of the proposed design.

• Journal of Fashion Business
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• v.17 no.6
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• pp.88-97
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• 2013

'Smart Clothes', which incorporate topnotch digital technology into fashion, are a leading fashion runner in this digital era. The purpose of the study is to first help develop a practical design for outdoor backpacks which are equipped with eco-friendly solar cells that facilitate recharging diverse smart devices during outdoor activities; and, secondly, to offer some practical data from the actual appropriation tests that will be used for manufacturing such products. This trial study finds out how to conjoin some practical IT devices with fashion items and mainly focusses on designing outdoor backpacks which are loaded with solar cells for recharging electric devices, and, later, experiments on designed backpacks with some smart phones to see how it works. According to the desired purposes of backpacks, all the features can be adjusted and modified such as the kinds of solar cell panels, materials, sizes, positions of attachment, weights, etc. Smart Clothes are highly functional and fashionable items that satisfy both practical and emotional purposes, and are being actively developed to serve consumers. This study proves that Smart Clothes or Smart Wear will have practical uses for outdoor activities and will possibly lead our smart lifestyles.

• ETRI Journal
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• v.43 no.2
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• pp.232-245
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• 2021

As wireless communication continues to develop in limited frequency resource environments, it is becoming important to identify the state of spectrum utilization and predict the amount needed in future. It is essential to collect reliable information for data analysis. This paper introduces a platform that enables the gathering of the scheduling information of a long-term evolution (LTE) cellular system without connecting to the network. A typical LTE terminal can confirm its assigned resource information using the configuration parameters delivered from a network. However, our platform receives and captures only the LTE signal over the air and then enables the estimation of the data relevant to scheduling for all terminals within an LTE cell. After extracting the control channel signal without loss from all LTE subframes, it detects valid downlink control information using the proposed algorithm, which is based on the error vector magnitude of depatterned symbols. We verify the reliability of the developed platform by comparing it with real data from mobile phones and service operators. The average difference in resource block utilization is only 0.28%.