• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.1047-1051
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• 2004

Charge amplifier systems benefit from the very wide dynamic range of PE accelerometers by offering flexibility in adjusting the electrical output characteristics such as sensitivity and range. They are well suited for operation at high temperatures. Modern charge systems feature improved low noise operation, simplified digital controls, and dual mode operation for operation with charge or IEPE voltage mode sensors. high impedance circuitry is not well suited for operation in adverse field or factory environments. The resolution of a PE accelerometer may not be specified or known since noise is a system consideration determined by cable length and amplifier gain. IEPE accelerometrs operate from a constant current power source, provide a high-voltage, low-impedance, fixed mV/g output. They operate through long, ordinary, coaxial cable in adverse environments without degradation of signal quality. They have limited high temperature range. IEPE sensors are simple to operate. Both resolution and operating range are defined specifications. Cost perchannel is lower compared to PE systems since low-noise cable and charge amplifiers are not required.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.4
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• pp.3-12
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• 2006

RFID (Radio Frequency Identification) system is expected to play a critical role providing widespread services in the ubiquitous period. However, widespread use of RFID tags may create new threats to the privacy of individuals such as information leakage and traceability. It is difficult to solve the privacy problems because a tag has the limited computing power that is not the adequate resource to support the general encryption. Although the scheme of [2] protects the consumer privacy using an external agent, a tag should compute exponential operation needed high cost. We propose Self Re-Encryption Protocol (SREP) which provides song privacy without assisting of any external agent. Our SREP is well suitable to low-cost RFID system since it only needs multiplication and exclusive-or operation.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.12 s.177
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• pp.77-86
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• 2005

This paper is about the development of Automatic FPC(flexible printed circuit) punching instrument for the improvement of working condition and cost saving. FPC is used to detect the contact position of keyboard and button like a cellular phone. Depending on the quality of the printed ink and position of reference punching point to the FPC, the resistance and current are varied to the malfunctioning values. The size of reference punching point is 2mm and the above. Because the punching operation is done manually, The punching accuracy is varied with operator's condition. Recently, The punching accuracy has deteriorated severely to the 2mm punching reference hall so that assembly of the K/B has hardly done. To improve this manual punching operation to the FPC, automatic FPC punching system is introduced. Precise mechanical parts like a 5-step stepping motor and ball screw mechanism are designed and tested and low cost PC camera is used fur the sake of cost down instead of using high quality vision systems for the factory automation. Test algorithms and programs showed good results to the designed automatic punching system and led to the increasement of productivity and huge cost down to law material like FPC by avoiding bad quality.

• The KIPS Transactions:PartC
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• v.14C no.5
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• pp.431-438
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• 2007

RFID system is core technology that construct ubiquitous environment for replacement of barcode technology. Use ratio of RFID system rapidly increase because the technology has many good points such as identification speed, storage space, convenience etc. But low-cost tag operates easily by query of reader, so the system happened user privacy violent problem by tag information exposure. The system studied many ways for security application, but operation capability of low-cost tag is about $5K{\sim}10K$ gates, but only $250{\sim}3K$ gates allocated security part. So it is difficult to apply security to the system. Therefore, this scheme uses dividing 64 bits and reduces arithmetic, so proposed scheme provide mutual authentication that can apply to low-cost RFID system. Existing methods divide by 4 and used 96 bits. However, that reduces 32 bits length for lightweight and reduced from communication number of times of 7 times to 5 times. Also, because offer security by random number than existing scheme that generate two random numbers, that is more efficient. However, uses hash function for integrity that was not offered by XOR arithmetic and added extension of proposed scheme. Extended scheme is not offered efficiency than methods that use XOR arithmetic, but identification distance is mode that is proposed secure so that can use in for RFID system.

• Journal of the Korea Safety Management & Science
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• v.2 no.3
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• pp.37-46
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• 2000

A company needs low cost and high efficient S/W tools to improve the white color productivity in daily operation, These needs may be satisfied by end-user knowledge management system to be suggested in this paper. We suggest that the end-user knowledge management is not made by specialized developer but directly made by end-users of some related managers using company-wide DB and department DB. We expect that this end-user knowledge management system will increase the efficiency of end-user daily operation and minimize the total life cycle cost of end-user computing system in industry. The suggested end-user knowledge management system has been tested in some companies through the training course.

• International Commerce and Information Review
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• v.7 no.2
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• pp.75-94
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• 2005

This study is focused on evaluating the computer-integrated just-in-time (CI-JIT) production system of a semi-conductor manufacturing firm in Korea. Approaching the mid-1980s, the emphasis was on low price, low-cost operations, and quality, especially in USA. American companies have shifted output to low-wage countries like the Philippines, Korea, Japan, Malaysia and allied countries that can make quality products at low prices. Korea and other Asian countries forego short-term profits to gain a solid foothold in a product market, recognizing that larger market share leads to lower cost and higher profit in the long run. They bring manufacturers and suppliers together to improve material management and operation management, using project teams that investigate topics, such as Just-In-Time(JIT)manufacturing, among others. The "Kanban" word means "card" in Japanese, and is used to indicate the desired final delivery schedule. The operation for a particular item produced is scheduled for a specific time. The same process is extended to the external suppliers. More recently, the cards are gradually being replaced by electronic procedures that follow the same concept. Its capacity must be capable of handling the various transactions required by the JIT coverage as well as some allowances for expanded applications.

• Journal of Forest and Environmental Science
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• v.32 no.2
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• pp.189-195
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• 2016

Logging equipment and method have a major influence on harvesting productivity and cost. This study investigated the productivity and operational costs of tree-length cable yarding system using HAM300, a domestically developed tower yarder. We tested HAM300 for thinning operation in Pinus densiflora stands at Gangreung, Gangwon-do on April, 2014. To assess the productivity we conducted time study for each stage of the operation. When the average time/cycle was examined for each stage of the operation, the longest was for yarding (241 sec), followed by delimbing (237 sec), felling (153 sec), and processing (103 sec). Furthermore, productivity for felling was $8.6m^3/hr$, followed by delimbing ($5.1m^3/hr$), yarding ($3.5m^3/hr$), and processing ($8.1m^3/hr$). The total cost for the tree-length logging system was $58,446won/m^3$, of which the majority was incurred by the yarding cost at $46,217won/m^3$ (79.3%), whereas the lowest cost was for felling at $2,359won/m^3$ (4.1%). We suggest that it is necessary to foster specialized operators and provide training in operating the tower yarder thereby implementing efficient harvesting system resulting from low-cost yarding.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.269-274
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• 1998

This paper describes a scaled model for PWM thyristor current-source inverter with a commutation circuit. The system consists of a 6-pulse thyristor bridge and an LC resonant circuit with thyristor switches, which offers thyristors to have turn-off capability for PWM operation with minimal switching losses. The proposed system can be used as a reactive power compensator with PWM operation for the utilitity application. There would be two advantages in the proposed system over the existing voltage source inverter. One is the low system cost due to using the conventional thyristors. Another is easy expansion of system operation voltage because th series operation of thyristor devices is already proven in HVDC system.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.735-742
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• 2007

To get competitiveness in international markets, it is essential to provide low acquisition, maintenance and operation cost with high reliability, availability and maintainability. It can be achieved by lowering development cost, making proper maintenance planning and scheduling strategies, allocating man power and logistic cost properly. In this paper, we introduces the research on making a model for estimating the life cycle cost of newly developing magnetic levitation train system in Korea. To develop a proper life cycle cost model, we broadly analyzed specs and standards and compared the life cycle cost model developed in other country. Finally, we suggests strategies to develop an unique model for the magnetic levitation train system developing in Korea.

• Journal of Biosystems Engineering
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• v.39 no.2
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• pp.134-141
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• 2014

Purposes: This study was to validate the Robotic Smart Work System that can provides better working conditions and high productivity in unstructured environments like bio-industry, based on a tele-operation system for fruit harvesting with low cost 3-D positioning system on the laboratory level. Methods: For the Robotic Smart Work System for fruit harvesting and cultivation management in agriculture, a vision based tele-operating system and 3-D position information are key elements. This study proposed Robotic Smart Farming, an agricultural version of Robotic Smart Work System, and validated a 3-D position information system with a low cost omni camera and a laser marker system in the lab environment in order to get a vision based tele-operating system and 3-D position information. Results: The tasks like harvesting of the fixed target and cultivation management were accomplished even if there was a short time delay (30 ms ~ 100 ms). Although automatic conveyor works requiring accurate timing and positioning yield high productivity, the tele-operation with user's intuition will be more efficient in unstructured environments which require target selection and judgment. Conclusions: This system increased work efficiency and stability by considering ancillary intelligence as well as user's experience and knowhow. In addition, senior and female workers will operate the system easily because it can reduce labor and minimized user fatigue.