• Applied Chemistry for Engineering
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• v.24 no.3
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• pp.219-226
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• 2013

Organic semiconductor-based soft electronics has potential advantages for next-generation electronics and displays, which request mobile convenience, flexibility, light-weight, large area, etc. Organic field-effect transistors (OFET) are core elements for soft electronic applications, such as e-paper, e-book, smart card, RFID tag, photovoltaics, portable computer, sensor, memory, etc. An optimal multi-layered structure of organic semiconductor, insulator, and electrodes is required to achieve high-performance OFET. Since most organic semiconductors are self-assembled structures with weak van der Waals forces during film formation, their crystalline structures and orientation are significantly affected by environmental conditions, specifically, substrate properties of surface energy and roughness, changing the corresponding OFET. Organo-compatible insulators and surface treatments can induce the crystal structure and orientation of solution- or vacuum-processable organic semiconductors preferential to the charge-carrier transport in OFET.

• Korean Journal of Materials Research
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• v.22 no.12
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• pp.717-721
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• 2012

Manganese dioxide ($MnO_2$) is one of the most important cathode materials used in both aqueous and non-aqueous batteries. The $MnO_2$ polymorph that is used for lithium primary batteries is synthesized either by electrolytic (EMD-$MnO_2$) or chemical methods (CMD-$MnO_2$). Commonly, electrolytic manganese dioxide (EMD) is used as a cathode mixture material for dry-cell batteries, such as a alkaline batteries, zinc-carbon batteries, rechargeable alkaline batteries, etc. The characteristics of lithium/manganese-dioxide primary cells fabricated with EMD-$MnO_2$ powders as cathode were compared as a function of the parameters of a manufacturing process. The flexible primary cells were prepared with EMD-$MnO_2$, active carbon, and poly vinylidene fluoride (PVDF) binder (10 wt.%) coated on an Al foil substrate. A cathode sheet with micro-porous showed a higher discharge capacity than a cathode sheet compacted by a press process. As the amount of EMD-$MnO_2$ increased, the electrical conductivity decreased and the electrical capacity increased. The cell subjected to heat-treatment at $200^{\circ}C$ for 1 hr showed a high discharge capacity. The flexible primary cell made using the optimum conditions showed a capacity and an average voltage of 220 mAh/g and 2.8 V, respectively, at $437.5{\mu}A$.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.9 s.351
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• pp.135-141
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• 2006

In order to prevent traffic accident, it is very important that the driver regulates the location of rear view mirror using the automatic seat regulation system which guarantees the maximum vision of the possibility for accuracy. In order to solve this problem the paper deals with the automatic seat control system which guarantees comfortable and safe seating and good visual field. Also a automatic car seat control algorithm has been developed to regulate the back mirror. Particularly, the automatic seat control algorithm function for the air bag operation in case of an accident has been added depending on passengers weight. Moreover when the driver passes a dangerous area an algorithm has been developed which gives the driver a naming sign and has been simulated in a ubiquitous environment. The simulation result proved that the Intelligence analysis for traffic accidents can reduce franc accidents more than 25% than the currently existing methods.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1616-1626
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• 2010

This paper will show how self-alarming EAS(Electronic Article Surveillance) system can improve its receiving performance of magnetic field signal and reduce false alarm using dual-band wireless communication. Our research improved the receiving performance and the areas of recognition of magnetic signal through the change of VLF receiving circuit and alarm transmitting method. In addition, we verified the reduction of false alarm by improvement of integrity and distance between tag and receiver through experiment. Thanks to our research, we can build the high performance and economical EAS with low false alarm on the multi gate store.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.3
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• pp.138-144
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• 2018

Inventory inspection is an important task to eliminate the inconsistency between real assets and inventory management systems, and it is performed periodically at the site. In the case of a large-sized property, it is mainly managed in an outdoor workshop or a warehouse. However, due to the large area of the outdoor area, it is relatively difficult to identify the quantity and location of the property and is also vulnerable to theft. To solve this problem, we proposed a method and system for performing a warehouse inventory inspection using an unmanned aerial vehicle (UAV) and Bluetooth low energy (BLE) beacons. The proposed method has the following advantages. First of all, if we carry out inventory inspection by utilizing UAV, we can minimize user's effort compared to existing methods. The method of recognizing the asset by attaching the BLE beacon is more costly than using the existing RFID technology, but it is advantageous because the recognition distance is increased and the battery life of the tag is drastically increased. We also designed a BLE beacon reader for the system and implemented a prototype to show the feasibility of the proposed system. The prototype is based on Genuino 101, which is a kind of arduino, and adds HM-10 and Neo-6m modules to provide Bluetooth and GPS functions. The BLE beacon reader was tested in outdoor, and attached in drone. We also developed an inventory checking system based on the web to display results of inventory checking. The proposed approach enables the users to automate the operation of inventory checking on an outdoor warehouse.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.1032-1040
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• 2010

This paper describes implementation of electonic seal (E-Seal) of a container based on ISO 18185 standard and development of monitoring systems checking E-Seal device and cargo states in the container for secure transportation from departure to destination. For lack of definition on confidentiality support in ISO 18185-4 standard, it is vulnerable to security attack such as sniffing. To cope with this, we developed encryption/decryption functions implementing RC5 and AES-128 standards and compared their performance. Experimental results showed that RC5 outperformed AES-128 in terms of time delay. In addition, RC5 had an advantage under the condition of large sized messages as well as CPUs with low performance. However, the portion of encryption/decryption processing time was less than 1 percent of response time including communication delay between E-Seal tags and readers. Hence, the performance difference between RC5 and AES-128 standards was trivial, which revealed that both specifications were allowable in developed systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10A
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• pp.987-996
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• 2008

In this paper, the conventional anti-collision algorithms, such as Channel Monitoring algorithm and Pulse Protocol algorithm are analyzed. To decrease tag identification time, and increase system throughput and efficiency, we propose a new reader anti-collision algorithm, Pulse Protocol-based Hybrid Reader Anti-collision Algorithm, using Slot-occupied Probability under dense reader environment. The proposed algorithm uses Slot-occupied Probability to improve the performance of Pulse Protocol Algorithm. That is, A reader checks Slot-occupied Probability after generating random backoff time. If Slot-occupied Probability is greater than 0, it uses another new random backoff time to avoid reader collision. We also compare the performance of the proposed algorithm with those of Channel Monitoring and Pulse Protocol algorithms in respect of identification time system throughput, and system efficiency. Simulation results show that the proposed algorithm has an increment of 5% of identification time and system throughput as increasing the number of readers.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.459-462
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• 2005

In this paper, we investigate the high precision location estimation algorithm in 2.45GHz band RTLS with multiple tags. The location is estimated in LOS environments, 300m ${\times}$ 300m area, and 2D coordinates adopting a TDOA scheme which is not necessitate the transmission time of tags. We evaluate the average estimation error in distance assuming that tags are randomly distributed and the readers(3${\sim}$8) are uniformly(equal space) placed in test area. In results, average estimation error is 3.12m and 1.47m at reader numbers of 4 and 8, respectively. Minimum estimation error is obtained when the accumulated receiving signal from a tag is 3 or 4 regardless of available reader numbers. The error is less than 3m, satisfies the specification of RTLS.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.7 no.4
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• pp.228-235
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• 2007

The main purpose of this paper is to manage the container property effectively at the container yard by applying the RTLS technology to the field of port logistics. Yet, many kinds of noises happen to be inputted with the distance value(between the reader and the tag) which is to be inputted into the location identification algorithm, which makes the distance value jumped due to the system noise of the ultrasonic sensor module and the measurement noise. The Kalman Filter is widely used to prevent this jump occurrence; the noises are eliminated by using the EKF(Extended Kalman Filter) while considering that the distance information of the ultrasonic sensor is non-linear. Also, the 3D RTLS system at the port container yard suggested in this research is designed not to be interrupted for its ultrasonic transmission by positioning the antenna at the front of each sector of the container where the active tags are installed. We positioned the readers, which function as antennas for location identification, to four places randomly in the absolute coordinate and let the positions of the active tags identified by using the distance data delivered from the active tags. For the location identification algorithm used in this paper, the triangulation measurement that is most used in general is applied and newly reorganized to calculate the position of the container. In the first experiment, we dealt with the error resulting in the angle and the distance of the ultrasonic sensor module, which is the most important in the hardware performance; in the second, we evaluated the performance of the location identification algorithm, which is the most important in the software performance, and tested the noise cancellation effects for the EKF. According to the experiment result, the ultrasonic sensor showed an average of 3 to 5cm error up to $45^{\circ}$ in case of $60^{\circ}$ or more, non-reliable linear distances were obtained. In addition, the evaluation of the algorithm performance showed an average of $4^{\circ}{\sim}5^{\circ}$ error due to the error of the linear distance-this error is negligible for most container location identifications. Lastly, the experiment results of noise cancellation and jump preservation by using the EKF showed that noises were removed in the distance information which was entered from the input of the ultrasonic sensor and as a result, only signal was extracted; thus, jumps were able to be removed and the exact distance information between the ultrasonic sensors could be obtained.

• Journal of Computing Science and Engineering
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• v.6 no.1
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• pp.40-50
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• 2012

Increase in the number of older people due to demographic changes poses great challenges to the social healthcare systems both in the Western and as well as in the Eastern countries. Support for older people by formal care givers leads to enormous temporal and personal efforts. Therefore, one of the most important goals is to increase the efficiency and effectiveness of today's care. This can be achieved by the use of assistive technologies. These technologies are able to increase the safety of patients or to reduce the time needed for tasks that do not relate to direct interaction between the care giver and the patient. Motivated by this goal, this contribution focuses on applications of acoustic technologies to support users and care givers in ambient assisted living (AAL) scenarios. Acoustic sensors are small, unobtrusive and can be added to already existing care or living environments easily. The information gathered by the acoustic sensors can be analyzed to calculate the position of the user by localization and the context by detection and classification of acoustic events in the captured acoustic signal. By doing this, possibly dangerous situations like falls, screams or an increased amount of coughs can be detected and appropriate actions can be initialized by an intelligent autonomous system for the acoustic monitoring of older persons. The proposed system is able to reduce the false alarm rate compared to other existing and commercially available approaches that basically rely only on the acoustic level. This is due to the fact that it explicitly distinguishes between the various acoustic events and provides information on the type of emergency that has taken place. Furthermore, the position of the acoustic event can be determined as contextual information by the system that uses only the acoustic signal. By this, the position of the user is known even if she or he does not wear a localization device such as a radio-frequency identification (RFID) tag.