• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.3
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• pp.53-60
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• 2012

The fall-of-potential method is commonly used in measuring the ground resistance of large-scaled grounding system and the current and potential auxiliary electrodes are horizontally arranged. Because the distances between the ground grid to be tested and auxiliary electrodes are limited in downtown areas, it is very difficult to measure accurately the ground resistance of large-scaled grounding system. In this paper, the fall-of-potential method of measuring the ground resistance with the vertically-placed current and potential auxiliary electrodes was examined and discussed. The validity and good accuracy of the proposed method of measuring the ground resistance were confirmed through various simulations and actual tests carried out in uniform and two-layer soil structures.

• JSTS:Journal of Semiconductor Technology and Science
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• v.9 no.2
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• pp.98-103
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• 2009

An RF test structure is proposed and its applicability is confirmed by measuring DC characteristics and high frequency characteristics. Effective mobility extraction is also performed to confirm the validity of proposed test structure. The area of suggested test structure consumed on wafer was decreased by more than 50% and its characteristics do not be degraded compared with conventional structure.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.2
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• pp.111-117
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• 2004

The low-power design of the A/D converter is indispensable to achieve the compact bio-signal measuring device with long battery duration. In this paper, new decimation filter structure is proposed for the low-power design of the Sigma-Delta A/D converter in the bio-instruments. The proposed filter is based on the non-recursive structure of the CIC (Cascaded Integrator Comb) decimation filter in the Sigma-Delta A/D converter. By combining the CSD (Canonic Signed Digit) structure with common sub-expression sharing technique, the proposed decimation filter structure can significantly reduce the number of adders for implementation. For the fixed decimation factor of 16, the 15％ of power consumption saving is achieved in the proposed structure in comparison with that of the conventional polyphase CIC filter.

• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.4
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• pp.328-333
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• 2002

The deeper the hierarchy of a inheritance structure is, the better the reusability of the structure is, but the more difficult the understandability and the maintainability of it is. On the contrary, the shallower the hierarchy is, the worse the abstraction of the inheritance structure is, but the better the understandability and modifiability of it is. Therefore, it is to be desired that a deep hierarchy of a inheritance structure should be split to be shallow for the maintainability of a system. This paper proposed a complexity metric that is based on DIT and NOC of Chidamber and Kemerer, and solved the ambiguity of the metrics of them, which was pointed out by Li. The metric is a simple and heuristic one for measuring the complexity of class inheritance structures by considering the number of ancestor classes and descendant classes and the depth of inheritance hierarchy. This provides a quantitative information for assessing the complexity of a inheritance structure in splitting it.

• Journal of the Korean Geophysical Society
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• v.10 no.1
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• pp.27-35
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• 2007

There are many risks in constructing tunnel-structure. To prevent these risks from occurring and secure safety, the precise and rapid survey of inside displacement of the tunnel is required. But nowadays the measurement of the crown settlement, convergency, and surface settlement depends on general kinds of method which use total station or level. In the way to provide data about maintaining structure according to recent improvement and progress of measuring technology, 3D laser scanning is used. It solves the problem of reliability in measuring displacement of existing structure, provides material that enables to estimate shape change of structure visually, and makes it possible to deliberate speedy countermeasure. By this three dimensioning it is possible to make efficient use of structure maintenance and field measurement.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.4
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• pp.301-308
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• 2016

In this study, a novel method referred as non-marker vision-based displacement measuring system(NVDMS) was introduced in order to measure the displacement of structure. There are two distinct differences between proposed NVDMS and existing vision-based displacement measuring system(VDMS). First, the NVDMS extracts the pixel coordinates of the structure using a feature point not a marker. Second, in the NVDMS, the scaling factor in order to convert the coordinates of a feature points from pixel value to physical value can be calculated by using the external conditions between the camera and the structure, which are distance, angle, and focal length, while the scaling factor for VDMS can be calculated by using the geometry of marker. The free vibration test using the three-stories scale model was conducted in order to analyze the reliability of the displacement data obtained from the NVDMS by comparing the reference data obtained from laser displacement sensor(LDS), and the measurement of dynamic characteristics was proceed using the displacement data. The NVDMS can accurately measure the dynamic displacement of the structure without the marker, and the high reliability of the dynamic characteristics obtained from the NVDMS are secured.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.433-437
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• 2008

It's essential to build an earth retaining structure at the beginning and end point of a tunnel constructed in a colluvium area. A large scale of colluvial soil may cause a problem to the stability of the excavation ground. An excavation in colluvium has different behavior characteristics from those in a sandy soil due to unstable elements and needs counter measures for it. There are few systematic research efforts on the behavior characteristics of an earth retaining structure installed in colluvial soil. Thus this study set out to collect measuring data from an excavation site at the tunnel pit mouth in colluvium and set quantitative criteria for the safety of an earth retaining structure. After comparing and analyzing the theoretical and empirical earth pressure from the measuring data, the lateral earth pressure distribution acted on the earth retaining wall was suggested.

• Journal of the Korean housing association
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• v.26 no.4
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• pp.23-32
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• 2015

The purpose of this research is to analyze characteristics and related factors of IAQ (Indoor Air Quality) in newly built wooden houses by measuring pre and post occupancy. The subjects were five wooden houses which were built with similar materials and completed from July to December 2013. Measuring factors were TVOC, HCHO, PM10, $CO_2$, CO, indoor temperature, and relative humidity. As the result of pre occupancy measuring, the houses that revealed the lowest TVOC concentration or HCHO concentration were satisfied with "the standard for newly built apartment houses". Therefore, IAQ by the wooden structures is considered to be in good condition. However, in cases of partial value exceeded the standard, the reason is analyzed to be the materials of molding, wrapping doors, built-in closet, or kitchen furniture, etc. rather than structure materials. Most PM10 concentration level showed slightly below "the standard for occupied multi-use facilities". Remaining of construction dust was considered to be the reason. As the result of post occupancy measuring, every value except of one subject's TVOC concentration was lower than pre occupancy, explaining the importance of natural ventilation.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1235-1239
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• 2003

On the base of network frame and protocol system of Ethernet the networked sensing technology based on Ethernet is studied and the design principles of industrial Ethernet measurement of control system is put forward, and the general structure model is built in the paper. An eight-bit economical MCU scheme is proposed, and a general scheme of distributed intelligent networked measuring and control equipment based on TCP/IP is designed too. A compact TCP/IP protocol stack are successfully implemented in eight-bit MCU. With C51 program language, method of modularized programming is applied in soft design. The problem of in-system modifying measuring and control strategy of its system is solved successfully by assigning memory dynamically and saving parameter with EEPROM, and it makes the intelligent networked measurement and control system can explain and analyses control strategy from PC. Experiment result shows that, the research of intelligent networked measurement and control equipment and system base on TCP/IP is successful, with flexible network, convenient usage, and good commonality.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.2
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• pp.148-156
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• 2016

The paper deals with improvement of a piezoelectric ultrasonic transducer for measuring both pipe thickness and flow velocity. The transducer structure is based on the conventional transducers for measuring flow velocity by obliquely transmitting ultrasonic waves to the flow direction. The transducer invented earlier for measuring flow velocity and pipe thickness had an advantage of including only one piezoelectric disc, but for the thickness measurement the ultrasonic wave had to be reflected twice in a wedge material to be transmitted vertically to a pipe, and thus the wave signal was too weak. The transducer has been improved to transmit waves for thickness measurement vertically to a pipe without any prior reflection by electrically connecting two piezoelectric discs, one for flow velocity and the other for pipe thickness measurement. By comparing the measured results of specimen thickness with the improved transducer and conventional transducers, the accuracies of the improved one have been evaluated in the pipe thickness measurements.