• 한국정보통신학회논문지
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• 제8권8호
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• pp.1640-1646
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• 2004

본 논문에서는 휴대인터넷 기술을 이용한 P2P 망 설계 및 다자간 VoIP 서비스제공 방안을 제안하였다. 본 논문에서는 이러한 서비스를 실시간으로 제공하기 위해서 휴대인터넷 기술을 이용하여 음성서비스의 가능성을 확인하였다. 연구결과 휴대인터넷 망에서 P2P을 이용한 VoIP 서비스 망을 설계하고 성능평가를 실시한 결과 만족할 만한 연구 결과가 나타나 향후 서비스를 하게 될 휴대인터넷에서 활용 가능성을 예상할 수 있었다.

• Journal of Biosystems Engineering
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• 제14권2호
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• pp.115-122
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• 1989

The objective of this study was to develop a portable auger for handling rough rice in bulk. For this purpose, a system analysis was taken for the systems of harvesting, drying, storage and transportation of rough rice and an optimal handling capacity of portable auger was determined. Then a portable auger of which capacity is 9.2 $m^3/h$ (Indica type rough rice, 19.5%, w.b.) was designed and manufactured by design requirements and tested. Test results showed that the performance of portable auger developed satisfied most design requirements.

• 전자공학회논문지A
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• 제33A권12호
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• pp.16-24
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• 1996

In this paper, the radiation pattern of the monopole antenna mounted on the portable phone is analyzed. The analyzed model consists of a rectangular conductor box and a monopole antenna. Even though the radiation pattern of the monopole has been well known, the monopole antenna mounted on the portable phone has not been fully studied. Because of the conductor box, portable phone acts as an unbalanced dipole antenna whoe radiation patterns deviate fro those of th econventional isolated monopole antenna. Therefore, the analysis of the radiation patterns of unbalanced dopole antenna is necessary. Using the moment method, its radiation patterns are analyzed and the numerical results are verified through the measurements. In addition, the radiation patterns depending on various length of the conductor box and the monopole antenna are also presented and the dimension of the portable phone which gives excellent radiation characteristics are derived from the analyzed results.

• 음성과학
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• 제10권2호
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• pp.35-43
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• 2003

General speaker verification systems improve their recognition performances by normalizing log likelihood ratio, using a speaker model and its background speaker model that are required to be verified. So these systems rely heavily on the availability of much speaker independent databases for background speaker model design. This constraint, however, may be a burden in practical and portable devices such as palm-top computers or wireless handsets which place a premium on computations and memory. In this paper, new approach for the GMM-based background model design used in portable speaker verification system is presented when the enrollment data is available. This approach is to modify three parameters of GMM speaker model such as mixture weights, means and covariances along with reduced mixture order. According to the experiment on a 20 speaker population from YOHO database, we found that this method had a promise of effective use in a portable speaker verification system.

• ETRI Journal
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• 제28권1호
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• pp.67-76
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• 2006

This study aims to identify the factors that influence adoption intentions towards portable Internet service, based on the individual characteristics that assist in creating markets and developing strategies. Two types of factors are defined: individual characteristics including demographics, existing services usages, prior knowledge, adoption attitudes, and service evaluations; and adoption intentions including the willingness to subscribe, subscription term, willingness to pay, usage type, and preferred terminal. The results indicate that the importance of demographic variables depends on adoption intentions, and that users of mobile Internet service and wireless LAN are probably targets for portable Internet service. Furthermore, the results demonstrate the need for an enhanced perception of the usefulness and ease of use of service, as well as an intensive marketing activity for potential users and a bearable innovation to stimulate the market for portable Internet service.

• 농업과학연구
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• 제38권3호
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• pp.525-532
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• 2011

The aim of this study was to develop a portable electronic nose system for freshness measurement of meats, which could be an alterative of subjective measurements of human nose and time-consuming measurements of conventional gas chromatograph methods. The portable electronic system was o optimized by comparing the measurement sensitivity and hardware efficiency, such as power consumption and dimension reduction throughout two stages of the prototypes. The electronic nose systems were constructed using an array of four different metal oxide semiconductor sensors. Two different configurations of sensor array with dimension were designed and compared the performance respectively. The final prototype of the system showed much improved performance on saving power consumption and dimension reduction without decrease of measurement sensitivity of pork freshness. The results show the potential of constructing a portable electronic system for the measurement of meat quality with high sensitivity and energy efficiency.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권9호
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• pp.2299-2311
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• 2013

As portable multimedia devices become more popular and smaller, the use of portable projectors is also rapidly increasing. However, when portable projectors are used in mobile environments in which a dedicated planar screen is not available, the problem of geometric distortion of the projected image often arises. In this paper, we present a geometric image compensation method for portable projectors to compensate for geometric distortions of images projected on various types of planar or nonplanar projection surfaces. The proposed method is based on extraction of the two-dimensional (2D) geometric information of a projection area, setting of the compensation area, and prewarping using 2D homography. The experimental results show that the proposed method allows effective compensation for waved and arbitrarily shaped projection areas, as well as tilted and bent surfaces that are often found in the mobile environment. Furthermore, the proposed method is more computationally efficient than conventional image compensation methods that use 3D geometric information.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1272-1277
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• 2004

GPS type portable-alarm-system is composed of satellite receiving equipment, signal transmission equipment, etc. Time errors occur because of the processing methods of the satellite receiving equipment and signal generator, the positional error of GPS itself, etc. With the recent rise of train speed, it becomes very important to secure the stability of portable-alarm-system from time errors, The present study estimated errors caused by the structure of portable-alarm-system, GPS errors. etc., and verified them. In addition, it examined the effects of such errors on portable-alarm-system according to train speed.

• Applied Science and Convergence Technology
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• 제25권3호
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• pp.61-65
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• 2016

Here, the rapid detection of Salmonella typhimurium by a portable surface plasmon resonance (SPR) biosensor in which the beam from a diode laser is modulated by a rotating mirror is reported. Using this system, immunoassay based on lipopolysaccharides (LPS)-specific monoclonal anti-Salmonella antibody was performed. For the purpose of orientation-controlled immobilization of antibodies on the SPR chip surface, the cysteine-mediated immobilization method, which is based on interaction between a gold surface and a thiol group (-SH) of cysteine, was adopted. As a result, using the portable SPR-based immunoassay, we detected S. typhimurium in the range from 10^7 CFU/mL to 10^9 CFU/mL within 1 hour. The results indicate that the portable SPR system could be potentially applied for general laboratory detection as well as on-site monitoring of foodborne, clinical, and environmental agents of interest.

• 반도체디스플레이기술학회지
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• 제20권1호
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• pp.7-11
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• 2021

The electrocardiogram(ECG) and heart rates are essential for diagnosing heart disease. However, conventional portable ECG devices are possible to only measure heart rates or have limitations in how and where they are measured. In this paper, a portable ECG system in which ECG waveforms and heart rates are displayed on smartphone screens is developed. A smartphone is used as display equipment instead of a computer screen for continuous monitoring. The developed ECG system filters and amplifies detected analog ECG signals. Next, it converts the amplified analog ECG signals into digital signals, then transmits to the smartphone via Bluetooth communication. This ECG system can display and store biomedical signals on a smartphone through the application. As a result, the waveform and heart rates of the developed portable ECG system has been confirmed to be similar to those of existing medical devices.