• Proceedings of the Safety Management and Science Conference
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• 2008.04a
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• pp.401-415
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• 2008

Upon the basis at the end of March 2005, we have the 38.91 million cellular phone subscribers over the country and the total diffusion rate of the cellular phone is reached up to 76.1%. At this moment, it can be said the most people use it since the demand is still going on. Turning to the operation company, this is serviced by the SK Telecom, LG Telecom, and KTF, and there are at least 6 manufactures producing it including Samsung, LG, KTF ever, Motorola an d SKY. Most users periodically change the service vendor to the others for buying new model or changing the service vendor. It is understood the customer's action occurred by the differences of the brand cognition. In this study, along with some parameters including the difference of the vendor's difference of satisfaction (mobile telecommunication, product), and the possibility to buy the product again, I am going to find out the relationship between the satisfaction of the provider's service.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.45
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• pp.145-154
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• 1998

The effects of secondary task on driving performance and subjective workload were investigated during a simulated driving. The driving performance was determined by the appropriateness of break timing. The driving simulator was provided by the Korea Road Traffic Safety Association. The subjective workload was tested by using a multidimensional measure such as NASA-TLX. Road was categorized into two types: narrow alley and wide street. The secondary task included pushing the number on the cellular phone, pushing radio channel, and conversing with a passenger. Seventeen subjects volunteered in the study. The data were analyzed by using SAS. Results showed that using the cellular phone and pushing channel during driving caused 3∼22% decline of driving performance and 42∼59% increase of subjective workload respectively. These results indicated that the secondary task could be potentially dangerous although there was not a significant performance decrease due to the notable increase of mental workload. In the future, if we can use a more sensitive and realistic driving simulator, the effects of secondary task under a dynamic driving situation can be investigated.

• Journal of the Korean Magnetics Society
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• v.11 no.3
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• pp.109-113
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• 2001

Presently, an inductor adapted at MMIC (Monolithic Microwave Integrated Circuit) which is used for cellular phone or PHS operates at quasi-microwave range over 800 MHz. However, a W-CDMA (Wideband Code Division Multiple Access) will use about 2 GHz range. Therefore magnetic film device should be compatible up to 2 GHz. We have deposited Co-Pd-Al-O system film using rf sputtering method which is expected up to 2 GHz, and investigated the effect of Pd content and magnetic field annealing. When Pd composition is 19%, Hk was 118 Oe, and ${\mu}$′showed flat frequency characteristics up to 1.5 GHz. The Q factor (=${\mu}$′/${\mu}$") was 23.3 at 1 GHz, 6.7 at 1.5 GHz and 1.5 at 2 GHz, respectively. Resonance frequency was 2 GHz. Therefore Co-Pd-Al-O thin film could be used at over 1 GHz, and also expected as an inductor material for wide band CDMA type cellular phone.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.3
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• pp.389-395
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• 2011

Since Elliptic Curve Cryptosystems(ECCs) support the same security as RSA cryptosystem and ElGamal cryptosystem with 1/6 size key, ECCs are the most efficient to smart cards, cellular phone and small-size computers restricted by high memory capacity and power of process. In this paper, we explicitly explain methods for finite fields operations used in ECC, and then construct some composite fields over finite fields which are secure under Weil's decent attack and maximize the speed of operations. Lastly, we propose a fast multiplier over our composite fields.

• Information and Communications Magazine
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• v.25 no.10
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• pp.18-24
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• 2008

RFID(Radio Frequency Identification) 기술은 사물에 전자 태그를 부착하여 무선 인터페이스를 통해 사물의 정보를 자동으로 취득 할 수 있는 기술이다. 물류의 재고관리나 자동화 처리를 위해 주로 사용되었으나 최근에는 Cellular phone, PDA등 휴대용기기 에 RFID리더가 탑재되어 기존의 응용 이외에 다양한 서비스를 만들어 내려는 시도들이 나타나고 있다[1],[2]. 이는 궁극적으로는 모든 사물에 컴퓨팅 및 통신 기능을 부여하여 언제, 어디서, 무엇이든 통신이 가능한 환경을 구현함으로써 이제까지 사람 중심(Person to Person)에서 사물 중심(Machine to Machine) 정보화 사회로의 새로운 변화 시도이며 RFID기술은 진정한 Ubiquitous세상이 만들어지기 위한 주요 기술로서 지속적으로 발전되고 적용되어야 할 기술임이 분명하다. 이러한 사회적인 요구에 만족하기 위해서 RFID 기술도 변화하고 있고 새로운 기술적 이슈들이 나타나게 되었다. 본고에서는 RFID 기술의 변화를 알아보고, 특히 UHF 대역 RFID 리더가 Cellular phone에 내장되기 위해 소형화 및 저전력화가 되면서 발생하는 문제와 이의 해결방안을 살펴보고자 한다.

• MALSORI
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• no.61
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• pp.113-123
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• 2007

The environmental differences between training and testing mode are generally considered to be the critical factor for the performance degradation in speaker recognition systems. Especially, general speaker recognition systems try to get as clean speech as possible to train the speaker model, but it's not true in real testing phase due to environmental and channel noise. So in this paper, the new method of weighting the frame-based likelihood according to frame SNR is proposed in order to cope with that problem. That is to make use of the deep correlation between speech SNR and speaker discrimination rate. To verify the usefulness of this proposed method, it is applied to the context dependent speaker identification system. And the experimental results with the cellular phone speech DB which is designed by ETRI for Koran speaker recognition show that the proposed method is effective and increase the identification accuracy by 11% at maximum.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1335-1340
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• 2001

The information technology brought us many kinds of conveniences to our life, but it also caused social problems such as privacy interference, unexpected personal information leaks, and nose generation by telephonic talks, etc. In this paper, the microphone system of the cellular phone is developed to prevent these problems caused by progress of information technology. The developed system was designed to detect only acoustic signals from a human being in the presence of various kinds of background noises. A windscreen was designed by use of micro-channels to eliminate the popping noise by the wind from the mouth of a speaker and four microphone array and signal processing techniques are applied to reduce background noise. The impact of the developed system was evaluated by experimental tests. The results show that the system can improve the required functions considerably.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.770-773
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• 2004

IT(Information Technology)분야의 발전과 함께 RT(Robot Technology)분야도 21세기의 유망한 첨단기술로 손꼽히고 있다. 현재의 로봇은 그동안 주류를 이루던 산업용 로봇과는 달리 소프트컴퓨팅, 인간친화 인터페이스, 상호작용기술, 음성인식, 물체인식, 사용자 의도파악 등 갖가지 최첨단 기술들이 요구되는 퍼스널 로봇이 각광을 받고 있으며, 특히 오락용, 교육용 로봇들로 대표되는 엔터테인먼트 로봇(Entertainment Robot)분야가 요즘 국내·외에서 활발히 연구되고 있는 실정이다. 엔터테인먼트 로봇은 정형화된 작업만을 하는 것이 아니라 다양한 환경에서 여러 가지 작업을 해야만 한다. 따라서, 장난감 로봇처럼 인간과의 감정대화가 가능한 지능 시스템을 갖춰야만 한다. 그러므로 본 논문에서는 IT분야와 RT분야의 접목으로 시너지 효과를 크게 얻을 수 있는 새로운 기술 개념인 RCP(Robotic Cellular Phone)에 대한 개념을 정의하고, RCP의 기능성 모듈 중 하나인 감성발향 모듈에 대한 기본적인 이론과 실험적 결과를 통하여 로보틱 셀폰의 감성발향 모듈의 우수성을 확인한다.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.1
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• pp.74-83
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• 2011

In this paper, we propose an architecture design of military operation system utilizing cellular networks. The main contribution of this paper is to provide a cost-effective military operation solution for ground forces, which is based on IT(information technology). By employing the cellular phones of officers' and non-commissioned officers' as the tools of operational communication, the proposed system can be constructed in the minimum duration and be built on the four components: command and control system, gateway, security system, and terminal(cell phone). This system is most effective for the warfare of limited area, but the effectiveness does not decrease under the total war covering the whole land of Korea. For the environmental change of near future, expanded architecture is also provided to utilize the functionalities of smart phones.

• Journal of Yeungnam Medical Science
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• v.21 no.2
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• pp.167-176
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• 2004

Background: Electromagnetic fields (EMF) are ubiquitous in modern society including medical field. As the technology of medical instruments and telecommunications has developed rapidly, it has influenced on our lives in many ways. Modern medical practice requires high quality medical equipments, which have a great deal of electromagnetic interference and susceptibility. The purpose of this study were to evaluate electromagnetic condition under usual clinical condition and to suggest a practical guideline in general hospital. Materials and Methods: The actual state of the electromagnetic interference in the medical field was studied under usual clinical conditions including operating rooms, intensive care units, magnetic resonance imaging unit, and hyperthermia unit. Results: There was considerable noise as a result of electromagnetic fields from medical equipments including electrosurgical units and hyperthermia unit, and cellular phones, which could induce serious functional derangements of functioning medical devices. Conclusion: It will be necessary to evaluate the individual electromagnetic situations under various medical conditions and to define a limited zone for cellular phone as well as reposition medical equipments to secure a safer medical practice and to minimize electromagnetic interference.