• Journal of Environmental Impact Assessment
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• v.28 no.3
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• pp.332-345
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• 2019

The purpose of the study is to evaluate the treatability of contaminated groundwater with TPH and (or) $Cr^{6+}$. Laboratory scale tests were performed for oil/water separation, dissolved air flotation (DAF), coagulation and precipitation, and filtration with sand and activated carbon respectively. Two times of oil/water separation tests for total 40 minutes of separation or separating time shows 90.2 % of TPH removal rate. In case of DAF test for high TPH sample, the TPH removal rates were not varied significantly by the variation of microbubble size. However, tests for low TPH samples show that TPH removal rate increases as microbubbles are smaller. When coagulant was added to sample for DAF test, TPH removal rate was increased 12.3 %. SS removal rate by DAF was 97.9 % at $16-40{\mu}m$ and it was increased as the size of microbubble is reduced. Tests for coagulation and precipitation were performed to evaluate the removal of $Cr^{6+}$ in groundwater. The increase of $FeSO_4$ dosage increased $Cr^{6+}$ removal rate in the coagulation and precipitation process. As the amount of activated carbon in the filter media increased TPH removal rate in the filtration process. SS removal rate by the filtration was 96.7 % similar to the results of DAF process tests. The filtration process treats TPH and SS. Best design parameters are determined as the size of sand is $425-850{\mu}m$ and the ratio of activated carbon and sand is 50:50.

• Journal of the Korea Institute of Building Construction
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• v.19 no.6
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• pp.503-510
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• 2019

Recently, construction technology of RC structures must be examined for creep in concrete. The factors affecting the creep prediction of concrete and the results of creep in domestic construction field were reviewed. The longer the creep test period and the higher the compressive strength, the higher the creep prediction accuracy. The higher the curing temperature, the higher the initial strength development of the concrete, but the difference in the creep coefficients increased over time. Based on the results of creep evaluation in the domestic construction field and lab. tests, a modified predictive model that complements the ACI-209 model was proposed. In the creep prediction of real members using general to high strength concrete, the test period and temperature should be considered precisely.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.5
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• pp.539-545
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• 2011

Combustion characteristics of industrial radiant tube (RT) burners with forced oscillating combustion technology are investigated using a real-scale (125,000 kcal/h) industrial RT burner facility in both laboratory and field tests. Three different types of industrial RT burners using a by-product gas from the iron-and-steelmaking process are examined in a laboratory facility equipped with a W-type RT. During the field tests, an industrial RT burner is characterized in a large facility equipped with multiple RTs. Their performance and emission controls are investigated under diverse operating conditions. The feasibility of the forced oscillating combustion technology is evaluated by the extent of $NO_x$ reduction and the efficiency improvement. These improvements are able to save energy, extend the RT lifetime, and enhance productivity. The operating conditions that achieve the best performance and emission control for each RT burner are determined.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.11
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• pp.93-100
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• 2005

In this paper, we implement the embedded speech recognition system to support various application services such as audio and video control using speech recognition interface on cars. The embedded speech recognition system is implemented and ported in a DSP board. Because MIC type and speech codecs affect the accuracy of speech recognition. And also, we optimize the simulation and test environment to effectively remove the real noises on a car. We applied a noise suppression and feature compensation algorithm to increase an accuracy of sppech recognition on a car. And we used a context dependent tied-mixture acoustic modeling. The performance evaluation showed high accuracy of proposed system in office environment and even real car environment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.9
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• pp.825-832
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• 2016

This paper describes the development of a data bus analyzer for use in avionics systems integration test. The data bus analyzer is equipped with MIL-STD-1553B, CAN and Ethernet interface cards which is incorporated in a majority of the avionics systems to accommodate a variety of interfaces. It has an individual hardware for a capture engine and a analyzing engine in order to perform the collection and the analysis of the bus data at the same time efficiently. It provides a data display function of the grid, 2-dimensional and 3-dimensional form to increase the data analysis efficiency. Verification of the data bus analyzer was carried out module unit testing and inter-module integration testing on the basis of the test procedures. Verification of interlocking requirement and usefulness of developed equipment was confirmed through an integration test result performed on a system integration laboratory of aircraft which is an actual testing environment.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.6
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• pp.414-420
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• 2012

In an effort to commercialization of energy saving aeration apparatus, panel-type aeration membranes were prepared from polyurethane sheet of J company in Korea having tensile strength higher than $400kg_f/cm^2$ with thickness of 0.5mm. Micropores of 100 m size were made by poring technique utilizing needles. From lab-tests in 450 L water tank at temperature of $20^{\circ}C$, the performance of aeration panels at 40 L/min aeration rate showed 5 mg/L DO in less than 3 minutes approaching saturation point of 8 mg/L within 8 minutes. The results show very high efficiency with $K_{La(15)}$ ($16.34hr^{-1}$), Standard oxygen transfer efficiency (SOTE 54.7%) and Standard aeration efficienct (SAE 7.88 kg/kwh). Other pilot scale test in a $2m^3$ water tank with water temperature ($19^{\circ}C$) and aeration rate (30 L/min) showed DO exceeding 5 mg/L within 8 minutes along with $K_{La(15)}$ ($5.8hr^{-1}$), SOTE (42.1%) and SAE (6.41 kg/kwh). These efficiencies represent 2~2.5 times higher than conventional aeration devices. Especially, the achievement of higher Oxygen Transfer Rate indicate higher commercial viability. Conventional aeration devices when applied to clean water and wastewater frequently cause problems due to differences in actual Oxygen Transfer Rate. Our actual tests with $40^{\circ}C$ animal farm wastewater resulted very high efficiencies with Oxygen transfer efficiency ($OTE_f$ 22.1%) and $OTE_{pw40}$ (39.6%).

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2757-2760
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• 2003

본 논문에서는 심장 돌연사(sudden cardiac death, SCD)의 주된 원인인 세동(fibrillation)을 낮은 에너지에서 효율적으로 제거할 수 있는 biphasic 자동형 제세동기를 개발하였다. 개발한 제세동기는 고전압 충 방전부와 신호처리부를 포함하는 하드웨어와 세동검출 알고리즘과 시스템 제어 알고리즘의 소프트웨어로 구성하였다. 개발한 시스템의 안정성과 효용성을 검증하기 위하여, 실험실 환경에서 160 번의 연속적인 충 방전 테스트를 통하여 시스템의 안정성을 확인하였으며, ECG simulator 에서 발생되는 6 종의 세동신호를 적용하여 100％의 실시간 검출능력을 확인하였다.

• The Transactions of the Korea Information Processing Society
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• v.7 no.11
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• pp.3584-3591
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• 2000

In this paper we propose measure for performance evaluationof character recognition, We used three commercial character recognizers and one laboratory character recognizer for test. The characteristics of each recognizer is compared by proposed evaluation standrd, and analyzed characteristrics For the input test data, KT test collection are used. KT test collection is composed of 1000 document images about and complete source text. In this paper we propose method for measuring recognition rage in character unit for evaluation of character recogrition, The recogrition rates are compared and analyzed by single feature characteristic or mixed feature characteristic.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.5
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• pp.1295-1302
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• 2010

This paper proposed indoor location recognition method based on RSSI(received signal strength indication) using the LVQ network. In order to verify the effectiveness of the proposed method, we performed experiments, and then compared to the conventional triangularity measurement method. In the experiments, we set up the system to the laboratory, divided the 40 section, and installed 6 nodes as a reference node. We obtained the log-normal path loss model of wireless channels, RSSI converted into the distance. The distance values used as the input of LVQ. To learn the LVQ network, we set the target values as section indices. In the experiments, we determined the optimal number of subclass, and confirmed that the success rate of training phase was 96%, test phase was 91%.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.439-439
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• 2021

하천에서는 물리적 및 생태적 측면에서 종횡적 연결성이 매우 중요하며 이를 통해 물리적 환경 변화에 따라 변화하는 생물의 종도 연속적으로 변화하여 이어진다. 하천에서 안정적으로 물이 흐르고 거기서 서식하는 어류들의 보호 및 생태계 보전을 위해 어류의 이동이 가능하도록 보 혹은 댐 등과 같은 하천 횡단구조물 설계 시 어도를 추가적으로 설치하고 있다. 어도는 어류의 이동이 차단 혹은 곤란한 경우 이동이 가능하도록 만들어진 수로를 의미한다. 국내에 설치된 보는 35,000개 이상으로 이 중 어도는 5,081개가 설치되어 있다. 우리나라의 하천설계기준의 어도설계기준은 2002년에 개정되었으며 보의 부대시설로 어도의 형식에 대해서 다루어졌다. 그러나 어도의 기능을 평가하고 효율성을 증대시키기 위하여 어도 내의 수리 특성을 정확히 파악하여야 하며 또한 어류거동 및 이동에 대한 특성을 고려하여 적절한 어도의 위치선정 및 설계유량을 선정해야한다. 이를 위해 본 연구에서는 2차원 수리해석모형(Kim et al., 2018)에 Lagrangian기반 어류이동모형을 결합한 수치모형을 개발하고 이를 수리실험결과(Tan et al., 2018)와 비교하여 검증을 수행하였다. 어류의 운동 및 생물학적 특성을 반영하기는 매우 어렵기 때문에 현장조사 및 실험실 테스트로 통하여 획득한 주요 특성만을 반영하였다. 이러한 시도는 최근 기후변화 및 하천의 자연성 회복을 위한 종횡적 연결성을 검토하고 어도기능을 평가할 수 있는 기술로 활용이 가능할 것으로 보인다.