• Agricultural and Biosystems Engineering
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• v.4 no.1
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• pp.8-15
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• 2003

In Korea, quality evaluation of dried oak mushrooms are done first by classifying them into more than 10 different categories based on the state of opening of the cap, surface pattern, and colors. And mushrooms of each category are further classified into 3 or 4 groups based on its shape and size, resulting into total 30 to 40 different grades. Quality evaluation and sorting based on the external visual features are usually done manually. Since visual features of mushroom affecting quality grades are distributed over the entire surface of the mushroom, both front (cap) and back (stem and gill) surfaces should be inspected thoroughly. In fact, it is almost impossible for human to inspect every mushroom, especially when they are fed continuously via conveyor. In this paper, considering real time on-line system implementation, image processing algorithms utilizing artificial neural network have been developed for the quality grading of a mushroom. The neural network based image processing utilized the raw gray value image of fed mushrooms captured by the camera without any complex image processing such as feature enhancement and extraction to identify the feeding state and to grade the quality of a mushroom. Developed algorithms were implemented to the prototype on-line grading and sorting system. The prototype was developed to simplify the system requirement and the overall mechanism. The system was composed of automatic devices for mushroom feeding and handling, a set of computer vision system with lighting chamber, one chip microprocessor based controller, and pneumatic actuators. The proposed grading scheme was tested using the prototype. Network training for the feeding state recognition and grading was done using static images. 200 samples (20 grade levels and 10 per each grade) were used for training. 300 samples (20 grade levels and 15 per each grade) were used to validate the trained network. By changing orientation of each sample, 600 data sets were made for the test and the trained network showed around 91 % of the grading accuracy. Though image processing itself required approximately less than 0.3 second depending on a mushroom, because of the actuating device and control response, average 0.6 to 0.7 second was required for grading and sorting of a mushroom resulting into the processing capability of 5,000/hr to 6,000/hr.

• Journal of Sensor Science and Technology
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• v.10 no.4
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• pp.250-258
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• 2001

In this study, a lightning warning system (LWS) which can predict a lightning return stroke is developed, and the LWS is based on the measurement of electric field intensity at the ground level. The LWS consist of a rotation-type field mill as an electric field sensor, an impedance changer, a two-stage amplifier, and a microprocessor unit. From the calibration experiment, the frequency bandwidth and the maximum resolution of the LWS are $DC{\sim}200\;[Hz]$ and 73 [V/m], respectively. Also, the LWS can measure the electric field strength caused by a thunderstorm up to 18.7 [kV/m] at the ground. To ensure the sensing ability of the developed LWS in an actual situation, computer simulation using thundercloud models was carried out, and the result showed that the LWS can monitor the movement of thunderclouds within 6 [km] from the observation site.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.132-137
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• 2004

On-Board Diagnostic(OBD) systems are in most cars and light trucks on the load today. During the 1970's and early 1980's manufacturers started using electronic means to control engine functions and diagnose engine problems. The CARB's diagnostic requirements to meet EPA emission standards have been designated as OBD with a goal of monitoring all of the emissions-related components, as well as the chassis, body, accessory devices and the diagnostic control network of the vehicle for proper operation. In this paper, we present a remote measurement system for the wireless monitoring of diagnosis signal and sensors output signals of ECU adopted KWP2000, united the OBD communication protocol, on OBD-compliant vehicle using the wirless communication technique of Bluetooth. In order to measure the ECU signals, the interface circuit is designed to communicate ECU and designed terminal wirelessly according to the ISO, SAE regulation of communication protocol standard. A microprocessor S3C3410X is used for communicating ECU signals. The embedded system's software is programmed to measure the ECU signals using the ARM compiler and ANCI C based on MicroC/OS kernel to communicate between bluetooth modules using bluetooth stack. The diagnostic system is developed using Visual C++ MFC and protocol stack of bluetooth for Windows environment. The self-diagnosis and sensor output signals of ECU is able to monitor using PC with bluetooth board connected in serial port of PC. The algorithms for measuring the ECU sensor output and self-diagnostic signals are verified to monitor ECU state. At the same time, the information to fix the vehicle's problem can be shown on the developed monitoring software. The possibility for remote measurement of self-diagnosis and sensor signals of ECU adopted KWP2000 in embedded system verified through the developed systems and algorithms.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.3
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• pp.385-396
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• 1999

In the process of structural design for large-scale structures with several thousands of degrees of freedom, a plethora of structural calculations with large amount of data storage are required to obtain the forces and displacements of the members. However, current computational environment with single microprocessor such as a personal computer or a workstation is not capable of generating a high-level of efficiency in structural analysis and design process for large-scale structures. In this paper, a high-performance parallel computing system interconnected by a network of personal computers is proposed for an efficient structural analysis. Two distributed structural analysis algorithms are developed in the form of distributed or parallel preconditioned conjugate gradient (DPCG) method. To enhance the performance of the developed distributed structural analysis algorithms, the number of communications and the size of data to be communicated are minimized. These algorithms are applied to the structural analyses of three large space structures as well as a 144-story tube-in-tube framed structure.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.3 s.309
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• pp.41-50
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• 2006

This paper presents a novel ultrasonic sensor system to overcome limited distance detection range that can be measured only more than 30cm by single ultrasonic transducer. This is accomplished by separation of receiving capacitive ultrasonic transducer from transmitting capacitive ultrasonic transducer. And hardwares and software of the system are described in detail. The system makes very close range as well as long range detect by wireless precisely. Frequency of trigger pulse is 10Hz, but it is very low frequency for transmitting data in wireless module. Therefore, for triggering between receiver and transmitter, an algorithm for mixing and distinguishing trigger pulse from carrier pulse by software is proposed. The system is designed by common microprocessor 8051. The performance of the proposed method has been assessed through two types. The first, transmitting and receiving transducer are put on both sides. And then, distance of two point is measured as far as 0mm. Secondly, transmitting transducer send out ultrasonic pulse and measure the time of flight(TOF) until a first echo from an object detected by the detached receiving transducer. The distance between the detached transducers and a reflecting object is measured as far as 7cm. Images of measured ultrasonic waves and TOF for two methods presented to prove effectiveness of results.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.163-167
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• 2008

This paper presents the analysis of tactile effects on different body parts according to the various vibration patterns. The experiments use a vibration pad made of 16 vibration elements in the form of $4{\times}4$ array. The vibration elements are controlled by a 8-bit microprocessor. The sound of gunshot initiates a vibration pattern on different body parts and its sensitivity is measured. The analysis of the experiments lead us to conclude that the vibration pad is the most realistic interface for shooting games and the shoulder part is the most sensitive part in the body. In addition, the most effective vibration pattern is the for the pattern which gives the sensation of spreading out from the center to the outside. This study analyzes the relationship between the human body parts and the tactile sensations by the various vibration patterns. The result of this study will be a good reference for user studies in the field of haptics based on the vibration.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.8
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• pp.921-926
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• 2015

For the over-heat protection purpose in power strip devices, over-current detection/protection circuits, such as bimetal, switching circuit, and microprocessor-based relay circuit, have been widely setup in high-end products. Most of these circuits are connected to the power line in parallel and, thus, they are sensitive to the line voltage and current distortion. Moreover, these protection circuits are often costly and, therefore, it is hard to meet the commercial requirements. A low-cost over-current detection circuit with the contactless current transducer is designed and tested in this paper. The detection circuit is galvanically isolated from the power line and, thus, less sensitive to the line voltage distortion. The experimental results show that the proposed circuit accurately operates despite of its simple structure and low-cost electronic parts.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.2
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• pp.267-271
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• 2014

Nuclear power plant data networks and their associated safety systems are being modernized to include many information technology (IT) networks and applications. Along with the advancement of plant data networks (PDN), instrumentation and control systems are being upgraded with modern digital, microprocessor-based systems. However, nuclear PDN is confronted significant side-effects, which PDN is exposed to prevalent cyber threats typically found in IT environments. Therefore, cyber security vulnerabilities and possibilities of cyber incidents are dramatically increased in nuclear PDN. Consequently, it should be designed fully ensuring the PDN meet all reliability, performance and security requirements in order to overcome the disadvantages raised from adaption of IT technology. In this paper, we provide technical security criteria should be used in design and evaluation of secure PDN. It is believed PDN, which is designed and operated along with these technical security critera, effectively protect against possible outside cyber threats.

• The KIPS Transactions:PartA
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• v.15A no.5
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• pp.259-268
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• 2008

Multi-Core processors have become main-stream microprocessors in recent years. Servers based on these multi-core processors are widely adopted in High Performance Computing (HPC) and commercial business applications as well. These servers provide increased level of parallelism, thus can potentially boost the performance for applications. However, the shared resources among multiple cores on the same chip can become hot spots and act as performance bottlenecks. Therefore it is essential to optimize the use of shared resources for high performance and scalability for the multi-core servers. In this paper, we conduct experimental studies to analyze the positive and negative effects of the resource sharing on the performance of HPC applications. Through the analyses we also characterize the performance of multi-core servers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.2
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• pp.230-236
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• 2009

In this paper, in order to utilize new and renewable energy a grid-connected parasol-type solar power generation system is presented. The proposed power system combining with commercial electric power system is designed to meet the need fur maximum power consumption and parasols for the people staying at beach during hot summer. Solar electric power can be charged in rechargeable batteries during day time and used to provide charged electric power to loads like lamps and fans during night time, A battery charge-discharge controller is required for the good performance of batteries to be charged. The presented battery controller is designed based on high performance microprocessor for precise charge-discharge operations. An alarm circuit to give notice of battery exchange time and other convenient functions are installed in the system. We implemented the proposed solar power generation system at East Sea beach during peak summer season to verify its productivity and performance by experiments.