• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.6 no.2
• /
• pp.119-125
• /
• 2007

In this paper, a multi-band folded planar monopole internal antenna for mobile handset applications is proposed. The proposed antenna has multi-resonances, which is different from a conventional folded monopole antenna, and it provides a wide bandwidth at high frequency bands. The measured impedance bandwidth (VSWR < 3) is 180 MHz and 1880 MHz in lower and higher frequency bands, respectively. The proposed antenna can effectively cover most wireless communication bands including CDMA, GSM, GPS, DCS, PCS, and W-CDMA, WiBro and S-DMB.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.17 no.6
• /
• pp.41-56
• /
• 2007

In this paper, we propose a specification-based intrusion detection system for WIPI(Wireless Internet Platform for Interoperability). In proposing the system, we focused on providing lightweight code, supporting multiple languages and hardware independence. The proposed system is based on an algorithm which detects an intrusion to main API of WIPI-HAL(Handset Adaptation Layer) and defines the prototype of mIDS(mobile IDS) API group that it can be added on the HAL. Moreover, we prove apply possibility through a WIPI emulator using java library.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.18 no.10
• /
• pp.1189-1195
• /
• 2007

We design and fabricate, in this parer, a triple band folded monopole antenna for the folder type mobile phone handset that can be served GSM/DCS/USPCS mobile phone system. Antenna structure is modified meander shape which is obtained both extension of antenna physical length for GSM band and same directional multi-currents flowing on the antenna conductor surface for DCS/USPCS band. This antenna has as good performances as high radiation resistance and gain increment, and would be applied to mobile phone handset that is not able to be performed by internal antenna. By measurement, fabricated antenna by the press process shows under VSWR 3:1 at closed folder state and 2:1 at opened folder state over whole GSM/DCS/USPCS band, and has maximum gain as -0.02 dBi for GSM, +0.2 dBi for DCS, +0.78 dBi for USPCS band with almost omnidirectional H-plane radiation pattern.

• The Journal of the Korea Contents Association
• /
• v.14 no.11
• /
• pp.389-397
• /
• 2014

Studies on switching intention have been one of the most interesting topics. In this paper we investigate empirically the factors influencing the mobile communication service switching intention. Our research model includes the relationship between 'switching intention' and 'habit', 'alternative attractiveness', 'present service satisfaction'. In addition, we try to find the effects that 'habit' and 'alternative attractiveness' give to 'switching intention' through 'present service satisfaction'. Finally, the moderating effects of 'handset subsidy' are examined. We analyze the model by Multiple Group Structural Equation Model. This proves that 'habit', 'present service satisfaction', and 'alternative attractiveness' give direct effects to 'switching intention'. And 'habit' and 'alternative attractiveness' give the indirect effects to 'switching intention' through 'present service satisfaction'. In addition, 'handset subsidy' has the moderating effects between 'switching intention' and 'habit'.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2008.05a
• /
• pp.947-951
• /
• 2008

Subsidiary business between mobile carriers and handset manufacturers has been banned by Korean regulator due to the concern that it may cause the unfair competition in the market. But the opinion that the current regulation has to be consolidated is increasing to follow recent market trends, ensuer the fair competition and increase the users' benefit. In this paper, I analysed trends of the mobile telecommunication market and proposed desirable direction of regulatory improvement.

• Journal of Information Technology Services
• /
• v.15 no.1
• /
• pp.81-96
• /
• 2016

This study analyzes how breach fee under long-term contract and/or cap regulation on the breach fee can affect the impacts of "Mobile Device Distribution Improvement Act" on handset bundle price, average revenue per unit (ARPU), and social welfare. We conduct comparative analysis with an economic model of duopoly competition in price when users are under long-term contract and the breach fee can be regulated. The results show that the Act lowers the equilibrium prices, lower than incumbent price without the Act. Price of non-dominant Mobile Network Operator (MNO) can be lower than poaching price without the Act if significant portion of switching cost is breach fee or the market is significantly asymmetric. Under the significant circumstances, the Act can raise ARPU even though it improves social welfare. By contrast, the Act increases consumer surplus without affecting social welfare if breach fee is the only source of user's switching cost and is capped by the regulation, and more symmetric market and the stronger cap leads to higher consumer surplus.

• Proceedings of the KIEE Conference
• /
• 2008.10b
• /
• pp.137-138
• /
• 2008

This paper proposes the modified image contrast enhancement technique for small-sized display of mobile handset. Sample images are user interface images, in which scaled up wVGA($800{\times}480$) from qVGA($320{\times}240$) that we can see easily in mobile handset. The display size of mobile handset is relatively small, so the goal of this paper is to simplify image contrast enhancement algorithm based on conventional HE (Histogram Equalization) algorithm and improve computational effectiveness to minimize power consumption in real hardware IC. In this paper, we adopt HE technique, which is classical and widely used for image contrast enhancement. At first, the input frame image is partitioned to temporal sub-frames and then analyzes gray level histogram of each sub-frame. In case that the analyzed histogram of some sub-frames deviates so much from reference level (it means that the sub-frame image components consist of too bright ones or dark ones), apply DHE(Dynamic Histogram Equalization) algorithm. In the other case, apply classical Histogram Linearization (or Global HE) algorithm. Also we compare the HE technique with gamma LUT (Look-Up Table) method, which is known as the simplest technique to enhance image contrast.

• Journal of Korea Multimedia Society
• /
• v.11 no.10
• /
• pp.1436-1445
• /
• 2008

Currently, mobile handset embeds many communication modules including CDMA and Bluetooth, and many applications are developed based on these modules. In this paper, we study about wireless vehicle diagnosis software and user interface based on bluetooth system on mobile handset. We developed Bluetooth communication system on protocol converter between OBD(On Board Diagnostics)-II system. Based on this system, we can communicate ECU(Engine Control Unit) and mobile device based on windows .NET compact framework platform. Therefore we can easily diagnose vehicle state and obtain engine data. All user interface and vehicle diagnosis systems on mobile handset are developed under windows .NET compact framework platform. Using this system we achieved several improvements over existing vehicle diagnostic system; 1) the software download and upgrade can be achieve on wireless environment, 2) no additional diagnostic devices are requires, which saves additional cost and we can diagnose the vehicle easily, 3) we can easily port our system on many embedded systems including PDA and navigator, etc.

• Communications of the Korean Institute of Information Scientists and Engineers
• /
• v.28 no.11
• /
• pp.9-22
• /
• 2010

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.10 no.2
• /
• pp.53-59
• /
• 2010

Android that was made by Google and Open Handset Alliance is the open source software toolkit for mobile phone. In a few years, Android will be used by millions of Android mobile phones and other mobile devices, and become the main platform of application developers. In this paper, we develop an application contents Booky based on Google Android flatform by using Webview merits and Google search engine. The features of the developed content are as follows. First, a mobile-based Web browser which has an advanced screen resolution and can support more faster viewer than normal web browser as it reduces the amount of data transmission. Second, efficient E-book search and reading functionality. In the performance evaluation, we show the results of simulation using AVD(Android Virture Device).