• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.3 no.6
• /
• pp.597-611
• /
• 2009

With the advent of ubiquitous computing society, many advanced technologies have enabled wireless sensor networks which consist of small sensor nodes. However, the sensor nodes have limited computing resources such as small size memory, low battery life, short transmission range, and low computational capabilities. Thus, decreasing energy consumption is one of the most significant issues in wireless sensor networks. In addition, numerous applications for wireless sensor networks are recently spreading to various fields (health-care, surveillance, location tracking, unmanned monitoring, nuclear reactor control, crop harvesting control, u-city, building automation etc.). For many of them, supporting security functionalities is an indispensable feature. Especially in case wireless sensor networks should provide a sufficient variety of security functions, sensor nodes are required to have more powerful performance and more energy demanding features. In other words, simultaneously providing security features and saving energy faces a trade-off problem. This paper presents a novel energy-efficient security architecture in an IEEE 802.15.4-based wireless sensor network called the Hybrid Adaptive Security (HAS) framework in order to resolve the trade off issue between security and energy. Moreover, we present a performance analysis based on the experimental results and a real implementation model in order to verify the proposed approach.

• Journal of KIISE:Computing Practices and Letters
• /
• v.12 no.2
• /
• pp.102-110
• /
• 2006

This paper explains the design and development of the stand-alone high sound quality Internet Radio system, which is aimed for a small embedded type audio device rather than a general PC type. This device is designed to work with an Internet connection. This kind of system is not standardized so far, and also the related algorithm is not open to the public. So it is necessary to analyze several receiving algorithms of current radio receivers, and develop our own hardware in order to overcome these obstacles, finally to get the high quality of sound radio. The main electronic components of this Internet Radio are TCP/IP interfaces, an audio MP3 decoder, an I/O interface, and a Flash Memory Card with advanced audio multicasting for the next-generation Internet Radio. Basic structures and implementation issues of the next-generation most-versatile digital music player, and Internet Radio receivers, are discussed.

• Journal of Digital Convergence
• /
• v.11 no.2
• /
• pp.279-285
• /
• 2013

The development of information networks and computer technology has become a foundation to open up a sea of information and knowledge. The recent popularization of smart devices has been used as a tool to easily obtain the desired information and knowledge. In this paper, a knowledge-sharing system using information and social networks based on smart devices is proposed. The proposed system consists of functions of an Internet information search for user queries, accumulated knowledge, and social network response from acquaintances. An evaluation for user satisfaction was conducted to analyze the efficacy of the proposed system. According to the experiment, the knowledge-sharing system using smart device information results in significant satisfaction compared to the general information search engines.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.12 no.3
• /
• pp.125-132
• /
• 2016

The European Telecommunication Standards Institute (ETSI) Technical Committee (TC) Reconfigurable Radio Systems (RRS) is standardizing the multi-mode Mobile Device (MD). The configuration of multi-mode MD is determined by the downloaded mobile communication standard software. In this paper, we introduce the Radio Library concept for multi-mode MD which is one of the key components of RRS standard. This paper also introduces the Standard Functional Block which is a part of Radio Library. A method for selecting efficiency SFBs for multi-mode MD is presented and a Radio Library is generated based on the selected SFBs. This paper also shows sample Standard Functional Block Set which included in Radio Library. In order to verify the compatibility of the generated Radio Library which was made by C language, we implement the LTE Rel-10 and Wi-Fi(802.11b) to show the efficiency of generating a mobile communication standard software based on the Radio Library. Then using the Prograph Visual Programming MartenTM 1.6.4, we compiled our LTE Rel-10 and Wi-Fi(802.11b) source code.

• International Journal of Costume and Fashion
• /
• v.17 no.1
• /
• pp.1-15
• /
• 2017

This study made use of a qualitative approach with an intrinsic case study to explore how handheld devices applications were integrated in teaching and learning in Textiles, Clothing and Design programmes. Participants of the study were purposively sampled from the Textiles and Clothing department at a selected university of Science and Technology in Zimbabwe comprising eight lecturers and thirty-two students. In-depth, focus group interviews and observations were used to gather data for the study. The findings of the study showed that participants were still at the stage of actively experimenting with very limited handheld device applications for the purposes of teaching and learning. Photoediters and digital cameras were the commonest applications used in most modules of the Textiles, Clothing and Design programmes. Though the photoediters and digital cameras were found to match the multimedia category of the Functionality framework, these were not fully utilised by students. It was recommended that there is need for the Textiles, Clothing and Design lecturers to provide opportunities for students to use a variety of applications on handheld devices for collaborative designing in practical modules of the programmes as these can encourage the development of critical skills necessary for creating innovative textiles and fashion designs.

• Journal of Energy Engineering
• /
• v.11 no.3
• /
• pp.230-236
• /
• 2002

In real-time power system control, it is essential to measure the power system variables which are voltage, current, real and reactive power, power factor, system frequency and etc. These variables can be estimated or calculated by the synchronized phasor informations of voltage and current. Therefore, the synchronized phasor measurement of voltage and current is very important to real-time power system control. So, we develop SPMD (Synchronized Phasor Measurement Device) for synchronized phasor measurement of voltage and current. In this paper, we present the design and implementation of SPMD for real-time phasor measurement and the test results of developed SPMD on 380 V 3 phase distribution line in laboratory with resistor load and RTDS (Real Time Digital Simulator).

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.11 no.3
• /
• pp.53-62
• /
• 2015

Recently, number of tablet or Smartphone users increased significantly in domestic and around the world. But violation of personal information such as leakage, misuse and abuse are constantly occurring by using mobile devices which is very useful in our society. Therefore, in this paper it will talk about the problems in the network environment of the mobile environment such as tablet and Smartphone, Mobile Malware, hacking of the public key certificate, which could be potential threat to mobile environment. This thesis will research for people to use their mobile devices more reliable and safer in mobile environment from invasion and leakage of personal information. In order to use Smartphone safely, users have to use Wi-Fi and Bluetooth carefully in the public area. This paper will research how to use App safely and characteristic of risk of worm and Malware spreading. Because of security vulnerabilities of the public key certificate, it will suggest new type of security certification. In order to prevent from the information leakage and infect from Malware in mobile environment without knowing, this thesis will analyze the improved way to manage and use the mobile device.

• Journal of Mechanical Science and Technology
• /
• v.20 no.12
• /
• pp.2094-2104
• /
• 2006

As demands for complex microstructures with high aspect ratios have increased, the existing methods, MEMS and LIGA, have had difficulties coping with the number of masks and fabricable heights. A microstereolithography technology can meet these demands because it has no need of masks and is capable of fabricating high aspect ratio microstructures. In this technology, 3D part is fabricated by stacking layers, 2D sections, which are sliced from STL file, and the Dynamic Image Projection process enables the resin surface to be cured by a dynamic image generated with $DMD^{TM}$ (Digital Micromirror Device) and one irradiation. In this paper, we address optical design process for implementing this microstereolithography system that takes the light path based on DMD operation and image-formation on the resin surface using an optical design program into consideration. To verify the performance of this implemented microstereolithography system, complex 3D microstructures with high aspect ratios were fabricated.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.389-392
• /
• 2005

In the maskless photolithography based on the Digital Micromirror Device (DMD) by Texas Instruments Inc. (TI), the micromirror array works as a virtual photomask to write patterns directly onto Flat Panel Display (FPD) at high speed with low cost. However, it is neither simple to generate region-based patterns for the micromirror array nor easy to deliver sequences of patterns for the micromirror controller. Moreover, the quality of lithography yields the precise synchronization between generating sequence of patterns and irradiation rate off micromirrors. In this study, the region-based pattern generating system for maskless photolithography is devised. To verify salient features of devised functionalities, the prototype system is implemented and the system is evaluated with actual DMD based photolithography. The results show that proposed pattern generating method is proper and reliable. Moreover, the devised region-based pattern generating system is robust and precise enough to handle any possible user specified mandate and to achieve the quality of photolithography required by FPD manufacturer.

• 한국HCI학회:학술대회논문집
• /
• 2008.02b
• /
• pp.614-623
• /
• 2008

본 연구는 사용자 만족 중심의 기존 사용자 경험 관련 연구들이 가지고 있는 한계를 보완하기 위하여 감정적 애착이라는 새로운 개념을 도입함으로써 사용자 경험 연구의 새로운 시각을 제공하고자 하는 목적으로 진행되었다. 이를 의하여 [연구 1]에서는 감정적 애착과 관련된 기존 이론들에 대한 조사를 통하여 사용자들의 디지털 기기에 대한 감정적 애착 형성에 영향을 미칠 수 있는 이론적 경험 요소로서 지각된 자아 일치감과 지각된 사회적 고양감이라는 개념들을 도출하였으며, 이를 기반으로 사용자 경험의 관점에서 새로운 이론적 모형을 개발하고, 한국의 핸드폰 사용자들을 대상으로 한 설문을 통하여 개방된 감정적 애착 형성 모형의 타당성을 실증적으로 검증하였다. 또한 [연구 2]에서는 5 개국 (한국, 미국, 독일, 러시아, 인도)에서 4 개의 디지털 기기 (핸드폰, MP3 플레이어, LCD TV, 냉장고) 사용자들을 대상으로 한 Contextual Interview 를 실시하여 실제 디지털 기기의 개발 및 디자인에 구체적인 시사점을 제공할 수 있는 경험 요소들을 추가적으로 도출하였다. 마지막으로 [연구 3]에서는 [연구 2]를 통하여 도출된 구체적인 사용자 경험 요소들을 [연구 1]에서 개방된 이론적 모형에 반영하여 구체화된 감정적 애착 형성 모형을 개방하고, 구체화된 모형의 타당성을 미국 핸드폰 사용자들을 대상으로 한 설문을 통하여 추가적으로 검증하였다.