• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기물성,응용부문
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• pp.224-226
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• 2001

In this paper, a novel high-voltage motor monitoring system (HVMMS) is proposed. This system monitors the insulation condition of the stator winding by on-line measurements of partial discharge (PD). Sensor, EMC (Epoxy-Mica Coupler) is used for PD measurement PD signals are continuously measured and digitized with a peak-hold A/D converter to build the database of the high-voltage motor's insulation condition. Also, this system can communicate with the central monitoring system via RS-485. This helps more efficient operation and maintenance of the generator.

• 정보보호학회논문지
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• 제33권5호
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• pp.787-799
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• 2023

가정에서 IoT 장비가 많이 활용되면서, IoT 장비를 통합하여 사용자의 편의에 맞게 사용하는 IoT automation system을 향한 관심도 많아졌다. IoT automation system에서는 사전 정의된 자동화규칙에 따라 IoT 장비의 정보를 수집하고, IoT 장비가 작동한다. 하지만 공격자는 패킷을 지연시켜 실제 상태와 시스템에서 인식한 상태의 불일치가 되는 시간을 만든다. 이 시간 동안 시스템은 사전 정의한 자동화 규칙대로 동작하지 않는다. 제안된 지연공격 탐지방법이 일부 있지만, 트래픽량이나 배터리에 민감한 IoT system에 적용하기에 제한사항이 있다. 본 논문에서는 IoT 시스템에 적용할 수 있는 실용적인 패킷 지연 공격 탐지 방법을 제시한다. 제안 방법은 메시지를 전송할 때, 메세지의 전송을 알리는 패킷을 브로드캐스트로 발송함으로써 서버가 이벤트의 발생을 인지할 수 있도록 한다. 평가를 위하여 Raberry pi로 구현된 IoT system을 구성하고, 패킷 지연 공격에 대하여 평균2.2초이내로탐지할 수 있음을 보였다. 실험 결과 소모 전류 Overhead는 초당 평균 2.5 mA, 트래픽 Overhead는 15% 발생하였고, 기존 제안된 탐지방법보다 효율적으로 Delay attack을 탐지할 수 있음을 밝혔다.

• 항공우주시스템공학회지
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• 제17권2호
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• pp.56-61
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• 2023

최근 국내·외 적으로 AI 기반의 MUM-T 복합전투체계 고도화와 이를 통한 산업의 활성화가 글로벌 이슈로 급부상하고 있다. 그러나 우리의 국방부 방위사업법은 무기체계 자체기기 중심으로 MUM-T 실증이 이루어져 무기체계의 운용 부분에 대한 고도화에 NATO 선도국 대비 다소 미흡한 것으로 판단된다. 우리의 미래 글로벌 UGV, UAV, UMS 등 MUM-T 복합전투체계의 국제경쟁력 강화를 위해서는 자율화 MUM-T 개념 정립, 자율화·상호운용성·데이터 표준화 기반의 국방 AI MUM-T 최상위 플랫폼 구축과 운용, 국가과학기술자문회의와 같은 대통령소속의 국방혁신위원회의 신설과 심의·자문 기능 강화·추가가 요구된다.

• 충청수학회지
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• 제29권2호
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• pp.347-359
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• 2016

In this paper, we show that the solutions to perturbed functional differential system $$y^{\prime}=f(t,y)+{\int_{t_0}^{t}}g(s,y(s),Ty(s))ds$$, have a bounded properties. To show the bounded properties, we impose conditions on the perturbed part ${\int_{t_0}^{t}}g(s,y(s),Ty(s))ds$ and on the fundamental matrix of the unperturbed system y' = f(t, y) using the notion of $t_{\infty}$-similarity.

• 약학회지
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• 제45권3호
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• pp.245-250
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• 2001

Aminoacyl tRNA synthetases of bacteria are known as potential targets for new anti-microbial agents. To isolate new inhibitors of bacterial methionyl-tRNA synthetases from natural sources, a new target-oriented screening system using whole cells which are over-expressing a target enzyme was developed. Approximately 8,000 culture broths of microorganisms from soils were tested by this screening system. Among them, ten culture broths was found to contain inhibitory activity against methionyl -tRNA synthetases of Escherichia coli. For the validation of the screening system, this new method was compared with in vitro enzymatic method. Seven out of 10 culture broths showed inhibitory activity against methionyl-tRNA synthetases of E. coli. This result showed that the new screening system was comparable to the enzyme assay. Thus we believe that our screening system as a new method can be applied for the screening of new antibiotics inhibiting bacterial methionyl-tRNA synthetases from natural products.

• Journal of Information Processing Systems
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• 제17권1호
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• pp.28-36
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• 2021

This paper proposes two novel methods to model and simulate a mobile Internet of Things (IoT) system using the discrete event system specification (DEVS) formalism. In traditional simulation methods, it is advantageous to partition the simulation area hierarchically to reduce simulation time; however, in this case, the structure of the model may change as the IoT nodes to be modeled move. The proposed methods reduce the simulation time while maintaining the model structure, even when the IoT nodes move. To evaluate the performance of the proposed methods, a prototype mobile IoT system was modeled and simulated. The simulation results show that the proposed methods achieve good performance, even if the number of IoT nodes or the movement of IoT nodes increases.

• 상하수도학회지
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• 제26권1호
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• pp.131-139
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• 2012

Field experiment was performed from June 2010 to July 2011 to evaluate pollutants removal efficiency in the constructed wetland system for the treated wastewater and the river water. The wetland systems were constructed near Gyungan river. Two different systems with meandering shape were compared for seasonal base and operational period base. Several kinds of aquaculture are planted through the corridor of wetland system. Average removal rate of BOD, T-N and T-P for A system were 15.8%, 14.8% and 26.5%, respectively. Average removal rate of BOD, T-N and T-P for C system were 23.5%, 27.8% and 10.6%, respectively. The effluent from two wetland systems often exceeded effluent water quality standards for wastewater influent, however effluent water quality standards for river water. However, the wetland system can be useful to treat polluted river water and effluent from wastewater plant. Removal rate of pollutants in seasonal variation was the highest in summer for BOD and T-N, however the removal rates of T-P were higher in spring and autumn than in summer.

• 전기학회논문지
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• 제65권12호
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• pp.2232-2239
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• 2016

IoT industry has been highlighted in the domestic and foreign country. Since most IoT systems operate separate servers in Internet to control IoT hardwares, there exists the possibility of security problems. Also, IoT systems in markets use their own hardware controllers and devices. As a result, there are many limitations in adding new sensors or devices and using applications to access hardware controllers. To solve these problems, we have developed a novel IoT hardware control system based on a mobile messenger. For the security, we have adopted a secure mobile messenger, Telegram, which has its own security protection. Also, it can improve the easy of the usage without any installation of specific applications. For the enhancement of the system accessibility, the proposed IoT system supports various network protocols. As a result, there are many possibility to include various functions in the system. Finally, our IoT system can analyze the collected information from sensors to provide useful information to the users. Through the experiment, we show that the proposed IoT system can perform well.

• 대한치과교정학회지
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• 제46권1호
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• pp.27-35
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• 2016

Objective: The aims of our study were to verify the validity of the T-Scan III system (Tekscan) as an objective occlusal evaluation tool, and to assess the differences between two occlusal indexes - the peer assessment rating (PAR) index and the American Board of Orthodontics objective grading system (OGS) - by comparing the scores derived from the T-Scan III system with the two occlusal indexes and analyzing the correlations between them. Methods: The final study sample included 48 adult volunteers (39 men and 9 women, mean age $24.14{\pm}3.16years$), after excluding 29 volunteers whose occlusion could not be evaluated by the T-Scan III system due to severe skeletal or occlusal problems. PAR index and OGS scores were assessed using dental study models, and measurements of centric occlusion, protrusive movement, and lateral excursion movement were obtained via the T-Scan III system. The results were analyzed to determine correlations. Results: Occlusal analysis by the T-Scan III system was clinically reliable (p < 0.05), and the PAR index and OGS scores were significantly correlated with several measurements obtained with the T-Scan III system (p < 0.05). Conclusions: The T-Scan III system is a quantitative and reliable method for occlusal evaluation, and represents a potential substitute for occlusal indexes. Compared to the PAR index, the OGS scores of more variables were significantly correlated with the T-Scan measurements.

• 충청수학회지
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• 제29권4호
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• pp.585-598
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• 2016

This paper shows that the solutions to the nonlinear perturbed differential system $$y^{\prime}=f(t,y)+{\int_{t_0}^{t}}g(s,y(s),T_1y(s))ds+h(t,y(t),T_2y(t))$$, have bounded properties. To show these properties, we impose conditions on the perturbed part ${\int_{t_0}^{t}}g(s,y(s),T_1y(s))ds,h(t,y(t),T_2y(t))$, and on the fundamental matrix of the unperturbed system y' = f(t, y) using the notion of h-stability.