• Journal of the Korea Society of Computer and Information
• /
• v.21 no.2
• /
• pp.25-32
• /
• 2016

In this paper, we design a middleware for context-awareness which provides compound contexts from diverse sensors on a mobile device. Until now, most of context-aware application developers have taken responsibility for context processing from sensing data. Such application-level context processing causes heavily redundant data processing and leads to significant resource waste in energy as well as computing. In the proposed scheme, we define primitive and compound context map which consists of relavant sensors and features. Based on the context definition, each application demands a context of interest to the middleware, and thus similar context-aware applications inherently share context information and procesing within the middleware. We show that the proposed scheme significantly reduces the resource amounts of cpu, memory, and battery, and that the performance gain gets much more when multiple applications which need similar contexts are running.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.6 no.1
• /
• pp.25-31
• /
• 2011

LEDs are becoming the most suitable candidate replacing traditional fluorescent street-light lamps because of its energy efficiency and high brightness. Furthermore, most countries are urging to pursue energy savings in conjunction with IT and sensor network. In order to conserve energy of LED lamp and ensure the safety of pedestrian, we propose a new smart control method for LED light system based on USN using compound sensors, such as illuminance, motion, temperature and humidity sensor. An elaborate simulation shows that the proposed system with a smart control based switching can reduce the energy by 40%, compared to the previous street-light system with a fixed time based switching.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.9
• /
• pp.125-132
• /
• 2002

We use a compound-cam twin arm structure and random tool access method to achieve a faster ATC (Automatic Tool Changer) system for the accurate position and rotation control of a tool magazine and an exchange am. Based on the data obtained from various sensors, it is possible to follow the sequence of commands in each control step for an exchange arm. However, it is not so easy to reduce the exchange time of the system because of the slow responses of the sensors and execution mode delays of PLC (Programmable Logic Controller) scan time. In this paper, we propose a new programmed limit-switch position control method to obtain the shortest possible delays for the random tool access method and compound-cam twin arm structure. With some experimental results, we have achieved below 0.9sec tool exchange time with the proposed method.

• International Journal of Highway Engineering
• /
• v.16 no.3
• /
• pp.51-57
• /
• 2014

PURPOSES : This study is to suggest tunnel length to spray curing compound, based on the field tests. METHODS : At first field test, length from the entrance of tunnel to wet wall was checked by visual survey. The second and third test, various sensors were installed in concrete or in tunnel, such as RH sensor, temperature sensor, portable weather station and etc.. And also, test for bleeding and retaining water of concrete were conducted to evaluate environmental effect on concrete pavement. RESULTS : The result of the field experiment for tunnel length to spray curing compound indicates that length changes depending on tunnel length, season, and location. Environmental condition of a short tunnel was not much different between location near entrance and at center of tunnel. However, in case of a medium and long tunnel, effect of outside environmental condition decreased, when location moved into tunnel center of it. CONCLUSIONS : From the testing results, it can be proposed that optimum tunnel length to spray curing compound is 60m for a medium and long tunnel, and whole length for a short tunnel.

• Proceedings of the Korean Society of Dyers and Finishers Conference
• /
• 2011.03a
• /
• pp.67-67
• /
• 2011

Recently, Phthalocyanine dye has attentions due to their excellent photochemical properties and used to optical applications such as chemical sensors. And azo groups can change photochemical properties in the UV irradiation because their molecualr structure reverse cis-trans isomer and changes cooperative motion, aggregation and so on. In this study, we synthesized the azo compound between amino pyridine and phenol. this azo derivative used the combination with 3-nitro phthalonitrile and makes phthalocyanine structure through the synthesis with 1,8-diazabicyclo[5.4.0]undec-7-ene(DBU), zinc acetate. Finally, we synthesized a new photoswiching dye zinc-phthalocyanine azo compound. This compound was studied by phothoswichiing phenomenon by UV irradiation and analyzed molecular aggregation through the SEM images.

• Ceramist
• /
• v.21 no.2
• /
• pp.59-74
• /
• 2018

Imaging in the Short Wave Infrared (SWIR) provides several advantages over the visible and near-infrared regions: enhanced image resolution in in foggy or dusty environments, deep tissue penetration, surveillance capabilities with eye-safe lasers, assessment of food quality and safety. Commercially available SWIR imagers are fabricated by integrating expensive epitaxial grown III-V compound semiconductor sensors with Si-based readout integrated circuits(ROIC) by indium bump bonding Infrared image sensors made of solution-processed quantum dots have recently emerged as candidates for next-generation SWIR imagers. They combine ease of processing, tunable optoelectronic properties, facile integration with Si-based ROIC and good performance. Here, we review recent research and development trends of various application fields of SWIR image sensors and nano-materials capable of absorption and emission of SWIR band. With SWIR sensible nano-materials, new type of SWIR image sensor can replace current high price SWIR imagers.

• Journal of Sensor Science and Technology
• /
• v.17 no.1
• /
• pp.69-74
• /
• 2008

VOCs (Volatile Organic Compound) sensors were fabricated using $SnO_2$nanowires-based thin films and its gas sensing behaviors were studied. The $SnO_2$ nanowires synthesized from a thermal evaporation process were dispersed in a solution and the sensor film was prepared by dropping the slurry on the substrate with the electrodes and an embedded heater. The gas response (Ra/Rg, Ra: resistance in air, Rg: resistance in gas) to $30{\sim}40$ ppm Benzene, Ethyl Benzene, o-xylene were in the range of $39{\sim}42$, which were significantly higher than those to 50 ppm of CO, $CH_4$ and $C_3H_8$ ($12{\sim}19$).

• Journal of Institute of Control, Robotics and Systems
• /
• v.21 no.12
• /
• pp.1178-1184
• /
• 2015

In conventional robotics, charge-coupled device (CCD) and complementary metal-oxide-semiconductor (CMOS) cameras have been utilized for acquiring vision information. These devices have problems, such as narrow optic angles and inefficiencies in visual information processing. Recently, biomimetic vision sensors for robotic applications have been receiving much attention. These sensors are more efficient than conventional vision sensors in terms of the optic angle, power consumption, dynamic range, and redundancy suppression. This paper presents recent research trends on biomimetic vision sensors and discusses future directions.

• Journal of the Korean Society for Precision Engineering
• /
• v.23 no.1 s.178
• /
• pp.129-135
• /
• 2006

In this study, a two-axis ultra-precision stage driven by piezoelectric elements is presented. The stage has a flexure-type parallel linear guide mechanism consisting of quad-symmetric simple parallel linear springs and quad-symmetric double compound linear springs. While the simple parallel linear springs guide the linear motion of a moving plate in the stage, the double compound linear springs follow the motion of the simple parallel linear spring as well as compensate the parasitic motions caused by the simple parallel linear springs. The linear springs are designed by rectangular beam type flexures that are deformed by bending deflection rather than axial extension, because the axial extension is smaller than the bending deflection at the same force. The designed guide mechanism is analyzed by finite element method(FEM). Then two-axis parallel linear stage is implemented by the linear guide mechanism combined with piezoelectric elements and capacitance type displacement sensors. It is shown that the manufactured ultra-precision stage achieves 3 nm of resolution in x- and y-axis within 30 ${\mu}m$ of operating range.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1993.11a
• /
• pp.69-71
• /
• 1993

Fluoride compound potentiometric cell oxygen sensors were fabricated for the measurement of oxygen pressure in the low temperature range (300。K-500。K). The disk type sensors consist of a reference Air(0$_2$):Ag, a solid electrolyte SrF$_2$, and a sensing metel Ag electrode. And the buried reference electrode type sensor have a NiO/Ni reference electrode. The open circuit emf of the cell showed high sensivity to oxygen gas (60mv) at the measuring temperature 20$0^{\circ}C$. Also, The buried reference electrode type sensor showed 30mv from 1% to 10% oxygen pressure range.