• Journal of Information Technology Services
• /
• v.8 no.4
• /
• pp.151-163
• /
• 2009

In this paper, we design and develop a personalized advertisement and information services system based on mobile RFID using RFID virtual tag. It is a system to perform the use of the contents information or the commercial transaction on the contents products through internet server connection by using RFID tag information with a mobile according as transmitting immediately to a cell phone after a tag generator derived RFID tag information to be substituted for the contents information being output at present, after being transmitted from a cell phone the information request signal on the contents information being output from video media. This service system provides a mechanism for gathering advertisement information left behind by many clients visiting advertisement sites for analysis of customers property, service model for selecting personalized services, and mechanism for providing them to customers who visited in a advertisement mall joined to the shopping site.

• Journal of Information Technology Services
• /
• v.9 no.4
• /
• pp.207-217
• /
• 2010

This paper is concerned with a protection system for the mentally handicapped, which is utilizing a GPS receiver and mobile communications. The protection system consists of a location notification equipment, a location identification and management server, and a cell phone of guardian. The location notification equipment is made up of a GPS receiver, a CDMA communication module and a microprocessor. The equipment transfers the location of the mentally impaired to the location identification and management server when the handicapped gets out of a certain bound of the designated facility. The server marks the handicapped's location on the map in the server and also notifies the guardian's cell phone of the locations. With applying the proposed protection system to social welfare organizations related to the mentally handicapped, it is expected to efficiently contribute to the promotion of the handicapped's welfare.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.6 no.2
• /
• pp.113-118
• /
• 2007

KPCS internal antenna in this paper, is designed and fabricated using the theory based on the folded monopole antenna. I propose folded monopole internal antenna which has high gain low profile structure with easy installation into the handset of mobile phone. Design frequency is 1.8 GHz that is a center frequency of Korea PCS frequency band, and the impedance variances due to change of antenna structure as a length and width are simulated. Measurements show that input VSWR range under 2:1 is 1.72 - 1.88 GHz, and radiated H-plane pattern is omnidirectional under passive state. Active sensitivities and output power of phone applied antenna are $-105\;{\sim}\;-108\;dBm$ and $22.5\;{\sim}\;23.6\;dBm$ max., respectively.

• Journal of Korea Multimedia Society
• /
• v.13 no.11
• /
• pp.1687-1697
• /
• 2010

The USIM-based AKA authentication process is essential to a mobile payment system on smart phone environment. In this paper a payment protocol and an AKA module are designed for mobile payment system which is suitable for openness smart phone environment. The payment protocol designs the cross authentication among components of the mobile payment system to improve the reliability of the components. The AKA module of mobile payment system based on 3GPP-AKA protocol prevents the exposure of IMSI by creating the SSK(Shared Secure Key) through advance registration and solves the SQN(SeQuence Number) synchronization problem by using timestamp. Also, by using the SSK instead of authentication vector between SN and authentication center, the existing bandwidth $(688{\times}N){\times}R$ bit between them is reduced to $320{\times}R$ bit or $368{\times}R$ bit. It creates CK and IK which are message encryption key by using OT-SSK(One-Time SSK) between MS and SN. In addition, creating the new OT-SSK whenever MS is connected to SN, it prevents the data replay attack.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.24 no.10
• /
• pp.1017-1026
• /
• 2013

Four countries are participating in exposure assessment for Mobi-Kids Study. Each country evaluates RF and ELF exposure from mobile phones considering telecommunication system and environment in the corresponding area. The results will be used to determine accumulation exposure level of each subject in case and control groups to assess the potential carcinogenic effects of childhood and adolescent exposure to radio frequency(RF) and extremely low frequency( ELF) from mobile phones on the central nervous system. This paper analyzes exposure types of mobile phones which have been used in Korea for about 10 years, based on Mobi-Kids protocol. It includes investigation of mobile phone models released in the domestic market, design of numerical phone models to represent each exposure type, and measurement of ELF radiation from mobile phones.

• Journal of Digital Convergence
• /
• v.11 no.12
• /
• pp.333-338
• /
• 2013

This paper was aimed to represent 3D design process to enable the construction design in a smart phone. The construction design was done in pattern units, by composing construction materials in components first, followed by assembling the components in pattern. Four types of views were constructed and each function was described to enable construction design in mobile environment. In addition, the skills needed for each view were described in detail through the libraries used. The process and calculation results were shown in mobiles how each view performed its function and behave worked together with a complementary way based on this implementation technique.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.20 no.10
• /
• pp.1021-1030
• /
• 2009

We propose optimization method of two-inductor loaded small loop antennas using simple genetic algorithm. To optimize the loop antennas for the RFID and the mobile phone band, we changed positions and values of the two inductors in the loop antenna. Visual basic was used to make genetic algorithm and to calculate fitness values by controlling the commercial EM software. The bandwidth of the optimized RFID loop antenna is 10 MHz at the center frequency of 922 MHz and that of the mobile phone antenna are 84 MHz and 266 MHz at the center frequency of 948 MHz(GSM band) and 1.81 GHz(DCS band), respectively.

• Transactions of Materials Processing
• /
• v.20 no.2
• /
• pp.110-117
• /
• 2011

The purpose of this work is to develop of a press forming process for mobile phone battery cover as an alternative to the current manufacturing process by laser welding. This press forming process consists of a combination of bending, side pressing and side bending operations. The dimensional error for each process was investigated by finite element(FE) analysis and the Taguchi optimization method. The spreading of the cover width in the side pressing process was adjusted by modifying the blank shape with a notch. The over-bending method was adopted to compensate the spring-back which occurs after bending. Forming experiments were performed to verify the reliability of the developed press forming process. In addition, the strength of the product was evaluated to verify the suitability of the battery cover manufactured with this new press forming process. The results of the forming experiments indicate that the dimensional accuracy of the battery cover is within the required tolerance. The strength of the battery cover was evaluated to 547N which is larger than required strength of 400N.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.16 no.3
• /
• pp.119-124
• /
• 2017

Machining optimization using typical computer-aided manufacturing (CAM) software mainly depends on tool paths, and it is impossible to predict the behavior of material or cutting force. In this paper, cutting force analysis simulation is performed on the Unibody Case of a mobile phone with the aim of optimizing cutting-force-based machining using the Third Wave Systems' AdventEdge Production Module. Machining time after optimization was shortened by 42% for roughing compared to pre-optimization, and actual machining time was reduced by 36.8%. For finishing, machining time was reduced by 92%, and actual machining time was reduced around 90%. A surface roughness analysis found that the post-optimization surface roughness was $1.16{\mu}m$ Ra, compared to a pre-optimization value of $1.75{\mu}m$ Ra.

• Journal of Information Processing Systems
• /
• v.12 no.3
• /
• pp.436-454
• /
• 2016

This research presents the battery discharge rate models for the energy consumption of mobile phone batteries based on machine learning by taking into account three usage patterns of the phone: the standby state, video playing, and web browsing. We present the experimental design methodology for collecting data, preprocessing, model construction, and parameter selections. The data is collected based on the HTC One X hardware platform. We considered various setting factors, such as Bluetooth, brightness, 3G, GPS, Wi-Fi, and Sync. The battery levels for each possible state vector were measured, and then we constructed the battery prediction model using different regression functions based on the collected data. The accuracy of the constructed models using the multi-layer perceptron (MLP) and the support vector machine (SVM) were compared using varying kernel functions. Various parameters for MLP and SVM were considered. The measurement of prediction efficiency was done by the mean absolute error (MAE) and the root mean squared error (RMSE). The experiments showed that the MLP with linear regression performs well overall, while the SVM with the polynomial kernel function based on the linear regression gives a low MAE and RMSE. As a result, we were able to demonstrate how to apply the derived model to predict the remaining battery charge.