• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.2
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• pp.113-119
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• 2020

The IoT-based sensor network is one of the methods that can be efficiently applied to maintain the facilities, such as bridges, at a low cost. In this study, based on LoRa LPWAN, one of the IoT communications, sensor board for cable tension monitoring, data acquisition board for constructing sensor network along with existing measurement sensors, are developed to create bridge structural health monitoring system. In addition, we designed and manufactured a smart sensor node for LoRa communication and established a sensor network for monitoring. Further, we constructed a test bed at the Yeonggwang Bridge to verify the performance of the system. The test bed verification results suggested that the LoRa LPWAN-based sensor network can be applied as one of the technologies for monitoring the bridge structure soundness; this is excellent in terms of data rate, accuracy, and economy.

• Journal of Yeungnam Medical Science
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• v.2 no.1
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• pp.183-190
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• 1985

The glucose nonfermenting gram-negative bacilli encountered about 10% of all gram-negative bacilli isolated from clinical material. Therefore, a rapid and correct identification of glucose nonfermenting gram-negative bacilli is impostent for a better management of infectious disease. There are many conventional systems for the Identification of glucose nonfermenting gram-negative bacilli but most of them have problems and difficulties. Commercial Kit Systems exist and they are too expensive for dally use 10 Korea because of high cost. Based on 12 selected tests we propose a new code system, MCRCODE-N for rapid and 10-expensive identification of glucose nonfermenting gram-negative bacilli. The selective 12 tests are oxidase, glucose oxidation motility, urease, DNase arginine dehydrolase, nitrate reduction, gelatin Liquefaction, esculin hydrolysis, mannitol oxidation, maltose oxidation, Lactose oxidation. The 12 tests are divided 4 group and then each group has 3 tests. The result of each group is expressed by the number as below. The positive test is given by specific number (1st test = 1, 2nd test = 2, 3rd test = 4), while any negative result is 0. Each 3 numbers of one group are added and make number of 1 digit. Four digit number is refered to the code book of MCRCODE-N system or MCRCODE system using computer (Apple-II model) created by authors. This MCRCODE-N system is suitable ones for our use 10 Korea. We propose the MCRCODEN-N system for clinical use.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.2
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• pp.137-141
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• 2011

Sunscreen is divided into the organic agent of UV absorption and inorganic agent of reflection. These are evaluated by sun protection factor (SPF) in-vivo test requiring high cost and time, while in-vitro tests are adopted commonly because of short test time, easy result collection. Generally, test method of SPF use SPF 290a by UV-vis spectrometer. The evaluate by SPF 290 has low reproducibility. Although analysis using UV-vis spectrometer has high reproducibility, it is hard to separated results of transmission, adsorption, and reflection. In this study, suggested method of elipsometer has some merit such as high reproducibility, easy separation of transmission/adsorption/re- flection, analysis using various incident angle. We tested the validity of elipsometer for SPF measurement, using commercially available sun-block (SPF 50).

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.5
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• pp.817-838
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• 2014

Test environment on the company that handles a large amount of data such as telecommunications companies and financial institutions, may not always be the same as the production environment, which is caused by conversion of important columns about information and limitation of storage capacity due to the construction cost. Therefore, SQL performance degradation that occurs when the test and production environments are not the same, which is an important cause of connecting to the unexpected failures of online transactions, and it generates financial loss of business, customer complaints, a decrease in reliability. In studies related SQL performance, it has so far been conducted mainly studies of tuning associated with DBMS Optimizer, and it has not been addressed issues of this sector. Therefore, in this paper, I verify the validity about presentation of the advanced SQL Performance-based IT application change management process, in order to prevent failures of the online transactions associated with poor performance of SQL generated by differences in test and production environments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.459-467
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• 2016

Recently, new open-cut modular construction method, which is built within a 5~7m depth below the road, was proposed for the near-surface transit system to ensure the economic feasibility of underground structures. In this paper, the precast modular construction method was developed for the low-cost and rapid construction of underground structures. For the experiment on the flexural performance of the modular slab connections, a total of eleven specimens were fabricated according to the test variables; section shape, joint type, lap length, and transverse reinforcement. The test results were compared with those of the specimens without loop joints. To verify the performance of the slab connections, the 4-point loading tests of precast RC members with loop joints were conducted. As a result of the test, the flexural performance of the half-depth specimens with a 200mm lap length of loop joints were confirmed to be similar to those of the specimens without joints.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.1
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• pp.129-134
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• 2014

We have developed a cost-effective and facile method to manufacture a pouch-type chemical vapor sampler. Originally, the sampler was developed by U. S. Army Natick Soldier Research, Development, and Engineering Center(NSRDEC) to determine the protective capability of individual protective ensembles or Man-in-Simulant Test (MIST). They used a selectively permeable high density polyethylene(HDPE) as front membrane and aluminum/ Nylon barrier film as an impermeable back sheet in order to mimic the actual adsorption process that occurs when the skin is exposed to chemical weapons. However, it costs over twenty dollars per sampler and the minimum of quantity is 2500 per order. In addition, it is inconvenient to employ a variety of adsorbents into the sampler, which could prevent MIST researchers to do various tests for development of MIST methodologies. Here, we report the simple method to manufacture the sampler in a laboratory scale. All the materials we used are easily obtainable and inexpensive. In addition, all the procedures we perform are generally known. We used methyl salicylate(MeS) vapor to be adsorbed into the sampler and employed several different adsorbents to evaluate the performance of samplers. The results obtained by home-made samplers and commercially avaliable one showed no significant differences. Also, MeS vapor was selectively adsorbed into the sampler depending on adsorbents. We conclude that home-made samplers are capable of collecting any kind of chemical vapor for a variety of purposes.

• KIISE Transactions on Computing Practices
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• v.21 no.10
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• pp.645-650
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• 2015

Tester Interface Software (TIS) provides all software functions that are necessary for a testing device to perform the test process on a memory semiconductor package from the time the device is put into the test equipment until the device is discharged from the equipment. TIS should perform the same work over all types of equipment regardless of their tester models. However, TIS has been developed and managed independently of the tester models because there are various equipment and computer models that are used in the test process. Therefore, more maintenance, time and cost are required for development, which adversely affects the quality of the software, and the problem becomes more serious when the new tester model is introduced. In this paper, we propose the Cross-platform Tester Interface Software (CTIS) framework, which can be integrated and operated on heterogeneous equipment and OSs.

• Journal of Welding and Joining
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• v.27 no.6
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• pp.80-86
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• 2009

The Cu-bearing PFS-700 steel which has yield strength over 700 MPa was developed to replace the existing submarine structural material, HY-100. The PFS-700 steel has a combination of good mechanical properties and superior weldability. Becaus of that, it can be welded without pre-heating. The application of PFS-700 steel to submarine or battle ship will give a great reduction of cost by omitting pre-heating or lowering pre-heat temperature. To develop pre-heating free welding consumables that match and take advantage of PFS-700 steel, new welding consumables have been designed for the GMAW, SAW processes and explosion bulge test(EBT) was conducted to see the reliability of welded structure. All welds were made without pre-heating, and the inter-pass temperature was below $50^{\circ}C$ for SAW50 and $150^{\circ}C$ for GMAW and SAW150. All EBT specimens show over 14% thickness reduction without through-thickness crack or crack propagation to the hole-down area. Tensile properties for all welding conditions show higher(GMAW) or similar values(SAW50, SAW150) to the base metal. Charpy impact values for the weld metal also show 163.5J(GMAW), 95.4J(SAW50) and 69.0J(SAW150), which meet the goal(higher than 50J) of this project.

• Structural Engineering and Mechanics
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• v.71 no.4
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• pp.391-405
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• 2019

Compared to the ambient vibration test mainly identifying the structural modal parameters, such as frequency, damping and mode shapes, the impact testing, which benefits from measuring both impacting forces and structural responses, has the merit to identify not only the structural modal parameters but also more detailed structural parameters, in particular flexibility. However, in traditional impact tests, an impacting hammer or artificial excitation device is employed, which restricts the efficiency of tests on various bridge structures. To resolve this problem, we propose a new method whereby a moving vehicle is taken as a continuous exciter and develop a corresponding flexibility identification theory, in which the continuous wheel forces induced by the moving vehicle is considered as structural input and the acceleration response of the bridge as the output, thus a structural flexibility matrix can be identified and then structural deflections of the bridge under arbitrary static loads can be predicted. The proposed method is more convenient, time-saving and cost-effective compared with traditional impact tests. However, because the proposed test produces a spatially continuous force while classical impact forces are spatially discrete, a new flexibility identification theory is required, and a novel structural identification method involving with equivalent load distribution, the enhanced Frequency Response Function (eFRFs) construction and modal scaling factor identification is proposed to make use of the continuous excitation force to identify the basic modal parameters as well as the structural flexibility. Laboratory and numerical examples are given, which validate the effectiveness of the proposed method. Furthermore, parametric analysis including road roughness, vehicle speed, vehicle weight, vehicle's stiffness and damping are conducted and the results obtained demonstrate that the developed method has strong robustness except that the relative error increases with the increase of measurement noise.

• Journal of Ocean Engineering and Technology
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• v.35 no.2
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• pp.141-149
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• 2021

The A60 class deck penetration piece is a fire-resistance apparatus installed on the deck compartment to protect lives and to prevent flame diffusion in the case of a fire accident in a ship or offshore plant. In this study, the sensitivity of the fire-resistance performance and approximation characteristics for the A60 class penetration piece was evaluated by conducting a transient heat-transfer analysis and fire test. The transient heat-transfer analysis was conducted to evaluate the fire-resistance design of the A60 class deck penetration piece, and the analysis results were verified via the fire test. The penetration-piece length, diameter, material type, and insulation density were used as the design factors (DFs), and the output responses were the weight, temperature, cost, and productivity. The quantitative effects of each DF on the output responses were evaluated using the design-of-experiments method. Additionally, an optimum design case was identified to minimize the weight of the A60 class deck penetration piece while satisfying the allowable limits of the output responses. According to the design-of-experiments results, various approximate models, e.g., a Kriging model, the response surface method, and a radial basis function-based neural network (RBFN), were generated. The design-of-experiments results were verified by the approximation results. It was concluded that among the approximate models, the RBFN was able to explore the design space of the A60 class deck penetration piece with the highest accuracy.