• Information and Communications Magazine
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• v.28 no.9
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• pp.21-28
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• 2011

M2M (Machine to Machine) 통신은 기존 사람 중심의 통신의 한계를 벗어나 새로운 융합 서비스의 영역을 만들어 내고 있다. 이러한 추세에 발맞춰 국제 표준화 기구에서도 M2M 통신에 적합하게 네트워크를 변경하는 노력을 하고 있으며, 특히 3GPP(3rd Generation Partnership Project) LTE-A(Long Tenn Evolution Advanced) 시스템에서는 2009년부터 본격적으로 표준화 작업을 진행하고 있다. 본고에서는 3GPP LTE 시스템을 기반으로 소량의 데이터를 송/수신하는 M2M 기가가 무수히 많이 존재하는 상황에서 발생할 수 있는 문제점을 고찰하고 이를 해결하기 위한 표준화 기술들을 소개한다. 특히 CN(Core Networks) 의 과부하 문제, 컨트롤 채널 (Control Channel)의 부족 문제 그리고 저전력 M2M 통신을 위한 전력 제어 문제를 해결하기 위한 기술을 소개하고 이를 바탕으로 앞으로의 M2M 기술 발전 방향을 제시하고자 한다.

• 전기의세계
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• v.18 no.6
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• pp.46-52
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• 1969

An analysis of the torque characteristics is to be expected of a twin stator induction machine with 2nd excitation is made. A twin stator induction machine has, through common rotor, 2nd excitating action one set to another relatively, but there are not its effect on the torque characteristics. However, by combination with the external fixed or simpled 2nd excitating e.m.f., variable torque-speed drives can be effectively achieved.

• Journal of Biosystems Engineering
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• v.35 no.6
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• pp.443-449
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• 2010

A machine vision-based instrument to measure a droplet size spectrum of a spray nozzle was developed and tested to evaluate its accuracy on measuring spray droplet sizes and classifying nozzle sizes. The instrument consisted of a machine vision, light emitting diode (LED) illumination and a desktop computer. The illumination and machine vision were controlled by the computer through a C++ program. The program controlled the machine vision to capture droplet images under controlled illumination, and processed the droplet images to characterize the droplet size distribution of a spray nozzle. An image processing algorithm was developed to improve the accuracy of the system by eliminating random noise and out-of-focus droplets in droplet images while measuring droplet sizes. The instrument measured sizes of the three different balls (254.0, 497.8 and $793.8\;{\mu}m$) and the measurement ranges were $241.2-273.6\;{\mu}m$, $492.9-529.6\;{\mu}m$ and $800.8-824.1\;{\mu}m$ for 254.0-, 497.84- and $793.75-\;{\mu}m$ balls, respectively. Error of the measured droplet mean was less than 3.0 %. Droplet statistics, $D_{V0.1}$, $D_{V0.5}$ and $D_{V0.9}$, of a reference nozzle set were measured, and droplet size spectra of five spray nozzles covering from very fine to extremely coarse were measured to classify spray nozzle sizes. Ninety percent of the classification results of the instrument agreed with manufacturer's classification. A comparison study was carried out between developed and commercial instruments, and measurement results of the developed instrument were within 20 % of commercial instrument results.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.4
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• pp.151-159
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• 2015

In this study, we developed an automated contact-type thickness measurement machine that continuously and precisely measures the thickness of a PCB module product using multi-LVDT sensors. The system contains a measurement part to automatically measure the thickness in real time according to the set conditions with an alignment supply unit and unloading unit to separate OK and NG products. The sensors were calibrated before assembly in the measuring machine, and precision and accuracy performance tests were also performed to reduce uncertainty errors in the measurement machine. In the calibration test, the precision errors of the LVDT sensor were determined to be $1-3{\mu}m$ as 0.1% at the measuring range. A measurement error of 0.8 mm and 1.0 mm thickness test standards were found to be $1{\mu}m$ and $4{\mu}m$, and the standard deviations of two 1.0 mm products were measured as $14{\mu}m$ and $8{\mu}m$, respectively. In the measurement system analysis, the accuracies of test PCB standards were found to be $2{\mu}m$ and $3{\mu}m$, respectively. From the results of gage repeatability and reproducibility (R & R) crossed, we found that the machine is suitable for the measurement and process control in the mass production line as 7.92% of total gage R & R and in seven distinct categories. The maximum operating speed was limited at 13 pcs/min, showing a value good enough to measure.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.11 s.176
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• pp.151-158
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• 2005

Micro-machine tool is essential in the micro/meso cutting for the sake of saving of space, resources, and energy. In this research, a micro-turning lathe was fabricated with piezoelectric feed drive mechanism, and motion of each axis was generated by stepwise mechanism with two piezo actuators. The resolution to drive the axis was $0.05{\mu}m$ and position accuracy less than $2{\mu}m$ was assured. From the positioning experiment, piezo feed mechanism is good enough for the micro machine tools. Many fuming experiments were carried out with diamond-cutting tools to evaluate cutting capability of a machine tool. Continuous flow type chip could be obtained even if the cutting speed was very low due to small diameter of workpiece. However, thorough investigation about machineability in micro/meso cutting is inevitable to assure high quality surface roughness in micro machine tool.

• Journal of Information Technology Services
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• v.11 no.1
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• pp.125-139
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• 2012

Machine-to-Machine(M2M) refers to technologies allowing both wireless and wired systems to communicate with other devices. The enhancement of wireless technologies and the reduced cost of wireless connection have contributed toward the development of M2M market. M2M market currently focuses on public sector services, As M2M can offer scalable and flexible services, M2M services are expected to be applied in various fields. However there are still some doubts on whether the demand for M2M services will be increased. This study investigates the feasibility of M2M services from the perspective of operators. Operators evaluate that M2M services will show high marketability but low profitability in general. In addition, operators predict that M2M services will show both marketability and profitability in the area of car maintenance, insurance, telematics, home and office security, shop floor maintenance, and real-time locating services for children protection. This study may offer some ideas of M2M business models based on empirical feasibility studies.

• Proceedings of the Korea Contents Association Conference
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• 2014.06a
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• pp.481-482
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• 2014

• The Journal of the Convergence on Culture Technology
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• v.9 no.2
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• pp.475-481
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• 2023

Softwares, especially like machine learning applications, affect human's life style tremendously. Accordingly, the importance of the cost model for softwares increases rapidly. As cost models, LOC(Line of Code) and M/M(Man-Month) estimates the quantitative aspects of the software. Differently from them, FP(Function Point) focuses on estimating the functional characteristics of software. FP is efficient in the aspect that it estimates qualitative characteristics. FP, however, has a limit for evaluating machine learning softwares because FP does not evaluate the critical factors of machine learning software. In this paper, we propose an extended function point(ExFP) that extends FP to adopt hyper parameter and the complexity of its optimization as the characteristics of the machine learning applications. In the evaluation reflecting the characteristics of machine learning applications. we reveals the effectiveness of the proposed ExFP.

• Transactions of Materials Processing
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• v.17 no.4
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• pp.257-262
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• 2008

The control of wire temperature is very important in the fine wire drawing process. The wire speed should be increased, and the wire temperature should be dropped as much as possible. Up to now, the process design of wire drawing process depends on the experiences of experts. In this study, a wire drawing process design method was proposed to increase the productivity. The proposed method of this study includes the pass schedule and the design of a multi pass wire drawing machine. A pass schedule was performed based on the calculation of the wire temperature. Also, a new multi pass wire drawing machine was manufactured to apply the designed pass schedule. Through the wire drawing experiment, the effectiveness of the proposed process design method was evaluated. The final drawing speed was increased from 1,100m/min to 2,000m/min without deterioration of final drawn wire.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.322-324
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• 2012

사람의 제어 없이 기기간에 통신하는 M2M(Machine to Machine) 통신은 우리의 삶의 중요한 부분으로 자리 잡아가고 있다. 특히 M2M의 한 부분으로써 헬스케어는 많은 연구가 진행되는 분야이다. 현재, 헬스케어 센서들은 환자의 상태를 모니터링하고 환자의 상태 정보를 의사에게 알려준다. 하지만, 만약 우리가 헬스케어 센서에 좀 더 지능성을 부여 할 수 있다면 환자가 위험 상황에 처하기 전 미리 판단하여 위험성을 의사에게 알려주어 보다 신속한 조치를 취하도록 할 수 있다. 본 논문에서는 M2M 네트워크의 헬스케어 시나리오에서 지능형 모바일 센서 에이전트의 구현을 설명한다. 이 센서 에이전트는 환자의 혈압을 측정하고 지능형 아답터와 매니저를 이용하여 원격의 의사에게 해당 정보를 알려준다.