• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.168-171
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• 2003

As vehicles are more intelligent for convenience and safety of drivers, the in-vehicle networking systems and smart modules are essential components for intelligent vehicles. However, for the smart module to widely apply to the IVN systems, two problems are considered as follows. Firstly, because it is very difficult that transducer manufacturers developed the smart module that supports the existing all IVN protocols, the smart module must be independent to the type of networking protocols. Secondly, when the smart module is exchanged due to its failure, it is necessary how the transducer is only exchanged without exchange of the microprocessor and network transceiver. This paper deals with the IEEE 1451 based smart module that describes the digital interface between a network transceiver and sensor module. Finally. efficiency of the IEEE 1451 based smart module was evaluated on the experimental model.

• Laser Solutions
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• v.12 no.1
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• pp.25-33
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• 2009

In laser-assisted machining (LAM), laser beam is used to locally increase the temperature of a workpiece and thus to enhance the machinability. In order to set the temperature of the material removal area of a workpiece at an optimal value, process parameters, such as laser power, feed rate, and rotational velocity, have to be carefully controlled. In this work, the effects of laser power and feed rate on the temperature distribution of a silicon nitride rotating at a constant velocity were experimentally investigated. Using a pyrometer, temperatures at various locations of the silicon nitride were measured both in circumferential and axial directions. The measured temperatures were fitted to a quadratic equation to approximate the temperature at the cutting location. The machining results showed that cutting force and tool wear were decreased when the temperature at the cutting location was increased.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.698-701
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• 2008

IETM(Interactive Electronic Technical Manual) has been introduced to construction industry recently, It is regarded as a useful tool for handling the data, procedures of the construction, but it can be similar to existing If-based systems, the PMIS (Project Management Information System) and the KMS(Knowledge Management System), without characterizing. This research is intended to investigate ITEM's basic concept, and to present the scheme discriminating Construction IETM from existing systems.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.3
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• pp.51-61
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• 2010

Nowadays, there are various networked systems with many computers. In most networked systems, a crucial objective is to keep transmitting and/or receiving data continuously even though failures exist. How can one make a computer continue transmitting and/or receiving data even when there are some errors on a link? Fault-Tolerant Ethernet (FTE) can be a solution to this question. In this paper, we propose a Localized Software-based Fault-Tolerant Ethernet (LSFTE). Our new approach fulfills the general FTE requirements. It takes advantage of redundant cable lines to maintain communication in a faulty environment. A software layer, which uses a simple and effective algorithm, is added above the LAN card driver software to detect and overcome faults. For our approach, there is no need to change the existing hardware or the end-use interfaces. Furthermore, the fault-detection time is reduced significantly compared to the conventional software-based approach.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.9
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• pp.941-946
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• 2011

The Loran-C, a radio navigation system based on TDOA measurements is enhanced to eLoran using TOA measurements instead of TDOA measurements. Many error factors such as PF, SF, ASF, clock errors and unknown biases are included in eLoran TOA measurements. Because these error factors can cause failure in eLoran navigation algorithm, these errors must be compensated for high accuracy eLoran navigation results. Compensation of ASF and unknown biases are difficult to calculate, while the others such as PF and SF are relatively easy to eliminate. In order to compensate all errors in eLoran TOA measurements, a simple GPS aided bias compensation method is suggested in this paper. This method calculates the bias as the difference of TOA measurement and the range between eLoran transmitters and the receiver whose position is determined using GPS. The real data measured in Europe are used for verification of suggested method and navigation algorithm.

• International Journal of Control, Automation, and Systems
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• v.6 no.5
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• pp.731-739
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• 2008

The docking and recharging system for a mobile robot must guarantee the ability to perform its tasks continuously without human intervention. This paper proposes two docking mechanisms with localization error-compensation capability for an auto recharging system. The mechanisms use friction forces or magnetic forces between the docking parts of the robot and those of the docking station. It is a structure to improve the allowance ranges of lateral and directional docking offsets, in which the robot is able to dock into the docking station. In this paper, auto-recharging system and the features of the proposed mechanisms are verified with experimental results using simple homing method.

• International Journal of Naval Architecture and Ocean Engineering
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• v.4 no.3
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• pp.291-301
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• 2012

A scalar metric for the assessment of hull surface producibility was known to be useful in estimating the complexity of a hull form of ships or large offshore structures by looking at their shape. However, it could not serve as a comprehensive measuring tool due to its lack of important components of the hull form such as longitudinals, stiffeners, and web frames attached to the hull surface. To have a complete metric for cost estimation, these structural members must be included. In this paper, major inner structural members are considered by measuring the complexity of their geometric shape. The final scalar metric thus consists of the classes containing inner members with various curvature magnitudes as well as the classes containing curved plates with single and double curvature distribution. Those two distinct metrics are merged into a complete scalar metric that accounts for the total cost estimation of complex structural bodies.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.2
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• pp.147-150
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• 2003

Water toxicity monitoring based on the continuous cultivation of Photobacterium phorphoreum is presented. Normally, after 10 days of operation, a dark variant, which emits no light, appears and dominates the population, resulting in a rapid decrease in bioluminescence. Therefore, to overcome this problem, a fluidized-bed reactor is used in which alginate-immobilized cells are grown and leaking cells are continuously released into the effluent Experimental results revealed that the dominance of dark variants was suppressed inside the immobilized beads, thereby mitigating the rapid loss of bioluminescence. Plus, a high dilution rate (1.2 h$\^$-1/) prevented the occurrence of other microbial contamination in the reactor The concentration and bioluminescence of the released cells were sufficient to measure the water toxicity for more than 4 weeks.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.566-570
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• 2001

Generally, grounding systems are responsible for the safe operation of a power system. Their performance guarantees equipment protection and personnel safety under condition of the limited ground potential rise and touch voltages as well as step voltages under ground fault conditions. Therefore, it is necessary to measure the ground resistance frequently for checking the performance of grounding system, In this paper the ground resistance measuring system using digital signal processor and high-performance L-C resonant band pass filter is presented. The signal current magnitude for measuring ground resistance in this system is $10^{-1}[A]\;to\;5\times10^{-2}[A]$ and the current frequency is 30[Hz].

• IEMEK Journal of Embedded Systems and Applications
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• v.1 no.2
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• pp.37-42
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• 2006

In this paper, we study a problem of providing reliable data transmission in wireless sensor network(WSN). A system with forward error correction9FEC) can provide an objective reliability while using less transmission power than a system without FEC. We propose the use of LDPC codes of various code rate (0.53, 0.81, 0.91) of FEC for WSN. Node-node-node interference is considered in the simulation in addition to AWGN in the channel. It is shown that the rate of 0.91 LDPC coded system obtained 7dB gain in signal to noise ratio over a system without FEC.