• Smart Structures and Systems
• /
• 제3권2호
• /
• pp.133-146
• /
• 2007

This paper addresses a new type of broad and stage-based hybrid carbon fiber reinforced polymer (HCFRP) sensor that is suitable for the sensing of infrastructures. The HCFRP sensors, a type of composite sensor, are fabricated with three types of carbon tows of different strength and moduli. For all of the specimens, the active materials are carbon tows by virtue of their electrical conductivity and piezoresistivity. The measurement principles are based on the micro- and macro-fractures of different types of carbon tows. A series of experiments are carried out to investigate the sensing performances of the HCFRP sensors. The main variables include the stack order and volume fractions of different types of carbon tows. It is shown that the change in electrical resistance is in direct proportion to the strain/load in low strain ranges. However, the fractional change in electrical resistance (${\Delta}R/R_0$) is smaller than 2% prior to the macrofractures of carbon tows. In order to improve the resistance changes, measures are taken that can enhance the values of ${\Delta}R/R_0$ by more than 2 times during low strain ranges. In high strain ranges, the electrical resistance changes markedly with strain/load in a step-wise manner due to the gradual ruptures of different types of carbon tows at different strain amplitudes. The values of ${\Delta}R/R_0$ due to the fracture of high modulus carbon tows are larger than 36%. Thus, it is demonstrated that the HCFRP sensors have a broad and stage-based sensing capability.

• 한국컴퓨터정보학회논문지
• /
• 제19권9호
• /
• pp.75-84
• /
• 2014

본 논문에서 우리는 다양한 센서를 사용하는 센서네트워크 환경을 구축하고 이를 단일 센서만을 고려하여 설계된 기존의 클러스터링 알고리즘에 적용하여 성능평가를 진행하였다. 실험에는 서로 다른 타입의 네트워크를 고려하였다. 첫 번째 네트워크는 모든 노드가 동일한 타입의 센서를 장착하는 환경이며, 두 번째는 3가지의 다종 센서를 사용한 네트워크 환경이다. 우리는 몇몇 클러스터링 기법을 데이터 정확성, 자원 고갈 노드 발생 시점, 네트워크 가용 에너지량, 고립 노드 비율, 그리고 네트워크 수명에 따라 성능 변화를 측정하였다. 성능 평가 결과에 의하여 기존 알고리즘은 다종 센서를 사용한 네트워크 유지에 비효율적이라는 사실을 입증하였다. 이에 따라 우리는 다종 센서를 고려한 클러스터링 알고리즘에 대한 연구가 요구됨을 제시하였다.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
• /
• pp.852-855
• /
• 2006

There is an increasing need to use data from different sensors in order to maximize the chances of obtaining a cloud-free image and to meet timely requirements for information. However, the use of data from multiple sensor systems is depending on comprehensive relationships between sensors of different types. Indeed, a study of inter-sensor relationships is well advanced in the effective use of remotely sensed data from multiple sensors. This paper was concerned with relationships between sensors of different types for vegetation indices (VI). The study was conducted using IKONOS and Landsat-7 ETM+ images. IKONOS and Landsat-7 ETM+ image of the same or about the same dates were acquired. The Landsat-7 ETM+ images were resampled in order to make them coincide with the pixel sizes of IKONOS. Inter-relationships of vegetation indices between images were performed using at-satellite reflectance obtained by converting image digital number (DN). All images were applied to topographic normalization method in order to reduce topographic effect in digital imagery. Also, Inter-sensor model equations between two sensors were developed and applied to other study region. In the result, the relational equations can be used to compute or interpret VI of one sensor using the VI of another sensor.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
• /
• pp.1088-1092
• /
• 2017

본 논문에서는 액체로켓엔진 가스발생기 연소시험에서 서로 다른 동압 센서를 통해 측정한 동압 결과를 비교하였다. 열 충격에 의한 영향으로 서로 다른 방식 및 제조사의 센서는 시간에 따른 동압 차이가 발생함을 확인하였다. 하지만, 연소불안정 분석에 있어 중요한 인자인 특성주파수와 RMS 값에 있어서는 센서에 따른 차이가 미미함을 확인하였다.

• 대한지리학회지
• /
• 제43권2호
• /
• pp.220-234
• /
• 2008

안전과 보안이 현대사회의 중요한 관심사로 등장하고 있고 그 대상 영역이 실내 공간으로 넘어서 도시로 확대되고 있다. 도심지역에 수 많은 감시 센서들이 설치 운영되고 있다. 많은 보안 모니터링 맥락에서 감시 센서/네트워크의 수행능력 혹은 효율성은 조명의 변화와 같은 환경 조건에 제약을 받는다. 서로 보완적인 상이한 유형의 센서를 설치함으로써 개별 유형의 센서의 고장 혹은 한계를 극복할 수 있다는 것은 익히 잘 알려진 사실이다. 입지 분석과 모델링의 관점에서 관심사는 어떻게 보완적인 상이한 유형의 센서들의 적절한 입지를 결정하여 보안기능을 강화할 수 있느냐 이다. 이 연구는 k 개의 상이한 유형의 감시 센서의 위치를 결정하는 커버리지 기반의 최적화 모델을 제시한다. 이 모델은 상이한 유형의 센서 사이의 공통 커버리지와 동일 유형의 센서 사이의 중복 커버지리를 동시에 고려한다. 개발된 모델은 도심 지역에 센서를 위치시키는데 적용된다. 연구 결과는 공통 및 중복 커버리지가 동시에 모델링 될 수 있으며, 두 유형의 커버지리 사이의 tradeoff를 보여주는 많은 해들이 있음을 보여준다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 춘계학술대회논문집
• /
• pp.318-322
• /
• 2001

This paper deals with sensing ability of smart sensor that has a sensing ability to distinguish materials according to surface types of smart sensor. We have developed a new signal processing method that can distinguish among different materials. The smart sensor was developed for recognition of materials. We made two types of smart sensors in our experiment. Then, we estimated the ability to recognize objects according to smart sensor type. We estimated the sensing ability of smart sensor with the $R_{SAI}$ method. Experiments and analysis were executed to estimate the ability to recognize objects according to surface types of smart sensor. Sensing ability of smart sensors was evaluated relatively through a new $R_{SAI}$ method. Applications of smart sensors are for finding abnormal conditions of objects (auto-manufacturing), feeling of objects (medical product), robotics, safety diagnosis of structure, etc.etc.

• 대한인간공학회지
• /
• 제34권2호
• /
• pp.191-198
• /
• 2015

Objective: As a cue for desired mood, we attempted to identify types of sitting postures when people are involved in various tasks during their working hours. Background: Physical behaviors in reaction to user contexts were studied, such as automated posture analysis for detecting a subject's emotion. Sitting postures have high feasibility and can be detected robustly with a sensing chair, especially when it comes to an office. Method: First, we attached seven sensors, including six pressure sensors and one distance sensor, to an office chair. In Part 1, we recorded participants' postures while they took part in four different tasks. From the seven sensors, we gathered five sets of data related to the head, the lumbar, the hip, thigh pressure and the distance between the backrest and the body. We classified them into four postures: leaning forward, upright, upright with the lumbar supporting, and leaning backward. In part 2, we requested the subjects to take suitable poses for the each of the four task types. In this way, we compared the matches between postures and tasks in a natural setting to those in a controlled situation. Results: We derived four types of sitting postures that were mapped onto the different tasks. The comparison yielded no statistical significance between Parts 1 and 2. In addition, there was a significant association between the task types and the posture types. Conclusion: The users' sitting postures were related to different types of tasks. This study demonstrates how human emotion can interact with lighting, as mediated through physical behavior. Application: We developed a posture-based lighting system that manipulates the quality of office lighting and is operated by changes in one's posture. Facilitated by this system, color temperatures ranging between 3,000K and 7,000K and illuminations ranging between 300lx and 700lx were modulated.

• 한국정보통신학회논문지
• /
• 제13권9호
• /
• pp.1928-1934
• /
• 2009

본 논문에서는 센서 투명성을 지원하는 센서노드 운영체제에서 MCU가 슬립모드일 때 센서의 전원도 같이 차단할 수 있는 전력관리 기법을 제안한다. 전원 차단이 가능한 센서인지를 구별하기 위해 센서의 종류를 이벤트 센서와 폴링 센서로 구분하고 이들을 지원하기 위한 스케쥴러를 설계하였다. 성능 분석을 위해 기존 센서네트워크 운영 체제인 Nano-Q+에서 센서에 대한 표준 인터페이스를 지원하는 센서 투명성 기능을 구현하고, MCU와 함께 센서를 자동으로 슬립모드로 바꿀 수 있는 전력 관리자를 설계, 구현하여 성능을 분석하였다.

• 한국연초학회지
• /
• 제27권1호
• /
• pp.134-140
• /
• 2005

The purpose of this study was the discrimination of different tobacco types by the E-Nose/tongue and the analysis of what human sensory attributes are correlated with e-instrument's sensors. Samples were made from five groups of Korean domestic tobacco leaves, aged burley and not aged, aged flue-cured and not aged and blending types of the four. Instrumental tests were conducted to discriminate characteristics among different tobacco samples by the E-Nose and the E-Tongue. Sensory attributes of tobacco tastes were impact, irritation, bitterness, hay-like, tobacco taste, smoke volume, smoke pungent and mouth cleanness. STATISTICA software was used to analyze correlation between the human sensory data and the raw data of e-instruments. Discrimination analysis can be achieved using principal components analysis (PCA) and discriminant factorial analysis(DFA). As a result, impact, bitterness, irritation, smoke volume and smoke pungent of human sensory attributes were correlated with data from the several clustered E-Nose sensors(p < 0.10). And bitterness, irritation, and smoke pungent of human sensory attributes were correlated with data from the E-Tongue sensors(p < 0.10). PCA plot by the E-Nose shows that aged tobacco and not aged were discriminated and DFA plot shows that three groups(aged burley, not aged burley and flue-cured) were discriminated. PCA plot by the E- Tongue shows that flue-cured tobacco was separated from burley. Our results indicated that the e-instruments are sensitive enough to distinguish among tobacco types and their several sensors are reacted to the human sensory attributes.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제51권6호
• /
• pp.246-252
• /
• 2002

This paper describes the acoustic emission measurement method to diagnose GIS for particles. We measured and analyzed the signals of acoustic waves using acoustic two types sensors with 125KHz and 50KHz resonant frequency respectively when the particles were dropped on the surfaces of circular plates and inside of GlS tanks. We found that the difference between peak outputs of two sensors depended on the types and materials of particles and the conditions of dropping position. These results showed that the outputs of 125KHz sensor were higher than those of 50KHz sensor in circular plate and 362㎸ GIS tank made of steel and vice versa in circular plate and 800㎸ GIS tank made of aluminum. The ratios outputs of 125KHz sensor to those of 50KHz sensor were 1.4 - 2.37 in 800㎸ GIS tank and were 0.5 - 1.0 in 362㎸ GIS tank. Therefore we knew that adaption of two types acoustic sensors which had different resonant frequencies as a very useful method in diagnosis of GIS.