• 지구물리와물리탐사
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• 제10권4호
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• pp.285-292
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• 2007

한반도 중부에서 얻은 자기지전류(MT) 탐사 자료의 dead band 주파수에서는 극심한 인공잡음의 영향이 나타난다. 이 연구에서는 송신원 위치 추정 기법을 MT 탐사 자료에 적용하여 인공잡음의 송신원 위치를 추정하였다. 일반적인 빔형성 기법은 전자기장 송신원 위치 추정에 적합하지 않으므로 정합장 처리 기법과 유전자 알고리즘을 이용하여 전자기장 송신원의 위치와 분극 방향을 계산하였다. 강한 잡음 신호에 대한 송신원 위치 추정 해는 매우 좁은 지역에 밀집되어 나타나지만 자연적인 MT 신호의 송신원 위치 추정해는 무작위적인 분포를 보여준다. 강한 잡음의 송신원은 경기도 서부 지역에 위치한다.

• 한국기후변화학회지
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• 제6권1호
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• pp.33-40
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• 2015

Forests are to be recognized as an important carbon sink under the UNFCCC that consist of above- and below-biomass, dead organic matter (DOM) such as dead wood and litter, and soil organic matter (SOM). In order to asses for DOM and SOM, however, it is relevant to land-use change matrices over last 20 years for each land-use category. In this study, a land-use change matrix was produced and its uncertainty was assessed using a point sampling technique with permanent sample plots in national forest inventory at Chungbuk province. With point sampling estimated areas at 2012 year for each land-use category were significantly similar to the true areas by given six land-use categories. Relative standard error in terms of uncertainty of land-use change among land-use categories ranged in 4.3~44.4%, excluding the other land. Forest and cropland covered relatively large areas showed lower uncertainty compared to the other land-use categories. This result showed that selected permanent samples in the NFI are able to support for producing land-use change matrix at a national or province level. If the $6^{th}$ NFI data are fully collected, the uncertainty of estimated area should be improved.

• 복식
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• 제51권4호
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• pp.5-14
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• 2001

Excavated costumes at the women's tomb in 17C have been sustained good condition. These materials give us that Jang ui(長衣) and so chang ui(소창의) with chechori(유), skirt, trousers(袴) reflects on women's fashion style at that time. By seeing these costumes, we can get the characteristics of costumes in mid-chosun era with chechori, skirt, jang ui, so chang ui etc. The features of chechori in this area are follows : form - diagonal gil, collar - kalkit and tangkokit, length - about 50cm, materials - silk, cotton, grass-cloth, kind - single, double. clothing padded with cotton wool etc. It is the first time that chang ui, one of Po, is excavated in this area. There are three pieces of jang ui which is significant data to study deeply on the costume in 1700's. Jang ui mainly made of silk in pattern, silk, cotton and decorated stylish printing on the robes. With these material and style, we can induce the mode of mid-chosun period. Through comparative studying we have many chances to understand women's the garment for the dead(염습의) in mid-chosun period.

• 로봇학회논문지
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• 제15권1호
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• pp.16-23
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• 2020

This paper describes an alignment algorithm that estimates the initial heading angle of AUVs (Autonomous Underwater Vehicle) for starting navigation in a sea area. In the basic dead reckoning system, the initial orientation of the vehicle is very important. In particular, the initial heading value is an essential factor in determining the performance of the entire navigation system. However, the heading angle of AUVs cannot be measured accurately because the DCS (Digital Compass) corrupted by surrounding magnetic field in pointing true north direction of the absolute global coordinate system (not the same to magnetic north direction). Therefore, we constructed an experimental constraint and designed an algorithm based on extended Kalman filter using only inertial navigation sensors and a GPS (Global Positioning System) receiver basically. The value of sensor covariance was selected by comparing the navigation results with the reference data. The proposed filter estimates the initial heading angle of AUVs for navigation in a sea area and reflects sampling characteristics of each sensor. Finally, we verify the performance of the filter through experiments.

• Journal of Information Display
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• 제13권1호
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• pp.17-20
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• 2012

The current panels for liquid crystal display (LCD) TV sets are all characterized by pins placed on two sides. To manufacture one type of panel, a dedicated mask is needed, and the production line should be started once. Moreover, the whole panel needs to be removed if a dead pixel is found. If the panel, however, will first be fabricated with pins placed on four sides and then divided by a cross-cut into four equal-sized panels with pins placed on two sides, one set of masks can be used to manufacture two types of LCD panels, which was referred to by the authors as dual mode. In this paper, the concept of the dual mode and its differences from the conventional way of producing panels are introduced. Its advantages in boosting production efficiency, improving the product's good rate, and lowering the production cost are also described based on case studies. Of particular importance is the fact that the dual mode is very suitable for the trial production of very-large-area LCD TV sets.

• 소음진동
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• 제10권4호
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• pp.615-622
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• 2000

Discharge valve mechanism for an electrodynamic-oscillating compressor is different from that of a conventional reciprocating compressor. It has a larger discharge port area, heavier valve mass and stiffer valve spring comparing with the reciprocating one. Since the motion of piston is not kinematically restricted as in conventional reciprocating compressors, the stroke of the piston can change sensitively with supplied boltage and load. Thus piston can impact with discharge valve occasionally. This work deals on dynamic analysis of discharge valve considering all of those different characteristics. Impact is considered by a spring-mass model, and the pressure fluctuation at the both sides of the valve is also included considering the discharge port area and valve spring preload. It is assumed that piston moves in the region of between top and bottom dead center not by calculating piston motion from an electrodynamic equation but by getting values through experiment. Discharge pressure fluctuation is calculated using Helmholtz modeling. Finally, dynamic model for a discharge valve is constructed. In order to validate the model analysis results, the valve motion is experimentally measured and compared with analysis.

• Structural Engineering and Mechanics
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• 제52권4호
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• pp.723-738
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• 2014

Prestressing is the most commonly employed technique in bridges and long span beams in commercial buildings as prestressing results in slender section with higher load carrying capacities. This work is an attempt to study the performance of a minimum weight prestressed concrete beam adopting a non-prismatic section so that there will be a reduction in the volume of concrete which in turn reduces the self-weight of the structure. The effect of adopting a non-prismatic section on parameters like prestressing force, area of prestressing steel, bending stresses, shear stresses and percentage loss of prestress are established theoretically. The analysis of non-prismatic prestressed beams is based on the assumption of pure bending theory. Equations are derived for dead load bending moment, eccentricity, and depth at any required section. Based on these equations an algorithm is developed which does the stress checks for the given section for every 500 mm interval of the span. Limit state method is used for the design of beam and finite difference method is used for finding out the deflection of a non-prismatic beam. All the parameters of nonprismatic prestressed concrete beams are compared with that of the rectangular prestressed concrete members and observed that minimum weight design and economical design are not same. Minimum weight design results in the increase in required area of prestressing steel.

• Journal of Ecology and Environment
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• 제42권1호
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• pp.12-19
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• 2018

Background: The objective of this study was to determine the relationship between soil environmental factors and halophyte distribution in the west coast of South Korea. Soils of our study sites were categorized into two groups: salt marsh and estuary marsh. Results: Salinity was higher in the salt marsh group than that in the estuary marsh group. However, total nitrogen, silt, and clay contents were higher in the estuary marsh group than those in the salt marsh group. Although altitude had a wider range in the salt marsh group, the mean altitude was higher in the estuary marsh group than that in the salt marsh group. Annual halophytes of seed propagation species were distributed parallel to the coast line on salt marsh. Higher coverage of vegetation was found in the area closer to the coast line. Plant density was higher near dead parental plants in estuary marsh, showing less difference in area that was more distant from the coast line. Conclusions: Results of canonical correspondence analysis (CCA) for vegetation distribution and sediment environmental factors and germination analysis in the coast line showed significant relationship with halophyte distribution. Therefore, they can be used as an indicator of coastal plant movement due to sea level rise.

• 한국방재학회 논문집
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• 제8권1호
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• pp.71-79
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• 2008

산불피해 임지의 식생복원 정도 및 문제점을 파악하기 위하여 산불발생 후 임목피해, 식생회복력 등의 조사 연구를 수행하였다. 소나무 고사율은 수간 및 수관의 피해흔적이 심할수록 피해율이 높았다. 산불피해지에 있어서 수관화에 의해 임분이 전소되는 피해를 받은 지역에서의 식생회복은 대부분이 매토종자 및 맹아에 의한 식생의 회복이 진행되었다. 식생회복과 복원력은 전생 임분의 식생상태와 토심에 따라서 차이가 나타났다. 인공복원의 경우 자작나무 조림지의 경우에는 병충해에 의한 피해가 발생하기도 하였다. 소나무, 해송 조림지의 경우 입지에 따른 생장차이 보다는 조사지내 개체목간의 생장차이가 다소 나타났다.

• Smart Structures and Systems
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• 제26권6호
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• pp.781-796
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• 2020

Prediction of total sediment load is essential in an extensive range of problems such as the design of the dead volume of dams, design of stable channels, sediment transport in the rivers, calculation of bridge piers degradation, prediction of sand and gravel mining effects on river-bed equilibrium, determination of the environmental impacts and dredging necessities. This paper is aimed to investigate and predict the total sediment load of the Wadi Arbaat in Eastern Sudan. The study was estimated the sediment load by separate total sediment load into bedload and Suspended Load (SL), independently. Although the sediment records are not sufficient to construct the discharge-sediment yield relationship and Sediment Rating Curve (SRC), the total sediment loads were predicted based on the discharge and Suspended Sediment Concentration (SSC). The turbidity data NTU in water quality has been used for prediction of the SSC in the estimation of suspended Sediment Yield (SY) transport of Wadi Arbaat. The sediment curves can be used for the estimation of the suspended SYs from the watershed area. The amount of information available for Khor Arbaat case study on sediment is poor data. However, the total sediment load is essential for the optimal control of the sediment transport on Khor Arbaat sediment and the protection of the dams on the upper gate area. The results show that the proposed model is found to be considered adequate to predict the total sediment load.