• Korean Journal of Cognitive Science
• /
• v.7 no.1
• /
• pp.57-74
• /
• 1996

This paper presents a comparison of recognition performance of the features used inthe recent handwritten korean character recognition.This research aims at providing the basis for feature selecion in order to improve not only the recognition rate but also the efficiency of recognition system.For the comparison of feature performace,we analyzed the characteristics of theose features and then,classified them into three rypes:global feature(image transformation)type,statistical feature type,and local/ topological feature type.For each type,we selected four or five features which seem more suitable to represent the characteristics of korean alphabet,and performed recongition experiments for the first consonant,horizontal vowel,and vertical vowel of a korean character, respectively.The classifier used in our experiments is a multi-layered perceptron with one hidden layer which is trained with backpropagation algorithm.The training and test data in the experiment are taken from 30sets of PE92. Experimental results show that 1)local/topological features outperform the other two type features in terms of recognition rates 2)mesh and projection features in statical feature type,walsh and DCT features in global feature type,and gradient and concavity features in local/topological feature type outperform the others in each type, respectively.

• Journal of Advanced Navigation Technology
• /
• v.16 no.2
• /
• pp.247-254
• /
• 2012

In this paper, we propose a concatenated diversity system to assure the data transmission reliability between flight type air nodes which move according to their atypical orbit, then its performance is analyzed using computer simulation and it is designed with hdl. The proposed system cannot only improve a bandwidth efficient and coding gain from diversity TCM code but also the reliability of data transmission is high. From the computer simulation result about bit error rate(BER) of the proposed system, we confirm that its BER performance is about 11dB greater than TCM code at $10^{-2}$ and about 11dB greater than space time block code at $10^{-3}$ which has a full diversity gain. In addition, when we compare its BER performance with space time trellis code which has both a diversity gain and a coding gain, the performance of the proposed system is greater than about 1.5dB at $10^{-5}$. Lastly, after designing the proposed system with HDL, we can confirm that the operation result is correct.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.31 no.4
• /
• pp.609-614
• /
• 2002

The characteristics of thermoluminescence (TL) and electron spin resonance (ESR) and organoleptic qualities of gamma-irradiated raisin and dried banana were investigated during storage at 4$^{\circ}C$ for 6 months. The minerals separated from non-irradiated raisins showed TL glow curve (TL$_1$) with very low intensity around 200~30$0^{\circ}C$, while the irradiated samples at 1 kGy or more showed glow curves with higher intensity around 18$0^{\circ}C$, with linear increase by irradiation dose ($R^2$=0.9684), which made it possible to identify irradiated samples during 6 months. Moreover, TL ratios (TL$_1$/TL$_2$) through the reirradiation step at 1 kGy enhanced confidence in the identification of irradiated raisins. The ESR signals of multicomponent lines resulted from crystalline sugar radicals were shown in irradiated banana, identifying irradiated samples. The ESR signal intensity was dependent on irradiation doses ($R^2$=0.8977) and the signals were stable enough to be detected by 6th month after storage. Considering tile marketability of irradiated dried fruits during 6 months at low temperature TL and ESR analyses were shown suitable for the identification of irradiated raisins and dried banana, respectively.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.4
• /
• pp.499-506
• /
• 2006

Response surface methodology was used to investigate the cookie manufacturing process with black rice flour. A three- variable, three-level central composite design was employed where the independent variables were the amount of black rice flour ($0{\sim}20%$), baking time ($10{\sim}14 min$), and sugar type (sucrose, aspartame and oligosaccarides). pHs of dough and cookie tended to increase with the addition of black rice flour. Moisture content of dough slightly increased with tile addition of black rice flour but nearly affected by baking time. Spread factor increased with the addition of black rice flour and it was more evident in the samples prepared with sucrose. L*-value decreased but a*-value increased significantly with the addition of black rice flour. Generally the amount of black rice flour in the sample did not affect the textural characteristics of cookie. As the amount of black rice and baking time increased, sensory flavor became stronger. Sensory sweetness as well as hardness increased but sensory color became darker with the addition of black rice flour. In addition, the response surface models developed in this study for most of physicochemical and sensory characteristics of black rice cookie were adequate.

• Journal of Korean Society of Forest Science
• /
• v.77 no.2
• /
• pp.235-241
• /
• 1988

This study was carried out to identify the variation of culm characteristics of Phyllostachys bambusoides associated with attitudinal gradient in Mt. Jiri. The results obtained were summarized as follows : It was estimated that the average temperature at the altitude of 400 meters of Mt. Jiri was $12^{\circ}C$ which was closely associated with the horizontal distributions. It was observed that frequency distribution of the culm height, D.E.H. and clear length from the altitude of 200 meters to 400 meters shown at higher than that from 500 meters to 600 meters, and that frequency of clear length/culm height showed about equal for both altitude ranges. In the case of culm height, D.E.H. and clear length/culm height, coefficients of variation ranged from 15 percent to 25 percent, and those of clear length were over 25 percent for both altitude ranges. It was observed that culm height, D.E.H., clear length and clear length/culm height among each altitude ranges were significant at the 1 percent level. The Duncan's Test of culm characteristics among altitude ranges distinguished bamboos of below 400 meters from bamboos of over 500 meters. The correlation coefficients among culm characteristics of Phyllostachys bambusoides associated with attitudinal gradient were shown to be highly significant. In conclusion, the variation of calm characteristics of Phyllostachys bambusoides was large for below 400 meters and these results suggest that planting of the species should be done below 400 meters.

• Journal of Korean Society of Forest Science
• /
• v.84 no.3
• /
• pp.333-342
• /
• 1995

A user - oriented computer model to aid designing forest road is developed to release the burden by increasing efficiency of time - consuming and laborious road design works. In this paper, the structures and functions of the model are discussed. The model consists of functional modules : 1)input module to treat survey data and design criteria ; 2)road design module to generate preliminary road layout, horizontal and vertical curvatures and curve widening ; 3)earthwork analysis module to determine the economic mass movement ; 4)report writer module to produce hard copies of engineering drawings for plan views, cross - sections and profiles, earthwork calculation sheets and mass movement diagrams. In addition, the report writer also provides the information on earthwork disturbance along the cut and - fill slopes. The modules are designed to be fully - integrated to enable the users to perform engineering analyses and evaluate design alternatives in a series of road - design procedures.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.7
• /
• pp.963-969
• /
• 2012

This study evaluated the physicochemical properties of brown rice (BR) and germinated brown rice (GBR) in Korea. The protein content of BR was significantly higher than that of GBR. The amylose content of BR and GBR ranged from 17.42 to 18.48% and from 17.50 to 19.69%, respectively. The GBR contained higher ${\gamma}$-aminobutyric acid (GABA) content than that of BR. In an RVA examination, pasting temperatures of BR and GBR were $67.97{\sim}68.03^{\circ}C$. Texture analysis test showed that GBR Yeonghojinmi had the lowest hardness and highest stickiness. In conclusion, this study showed that compared to BR, GBR has a much softer texture, improved eating quality and increased GABA content.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.48 no.10
• /
• pp.791-799
• /
• 2020

Launched in October 2019, Northrop Grumman's MEV-1 was the world's first unmanned mission demonstrating the practical feasibility of on-orbit servicing. Although the concept of on-orbit servicing was proposed several decades ago, it has been developed to various mission concepts providing services such as orbit change, station keeping, propellant and equipment supply, upgrade, repair, on-orbit assembly and production, and space debris removal. The historical success of MEV-1 is expected to expand the market of on-orbit servicing for government agencies and commercial sectors worldwide. The on-orbit servicing essentially requires the utilization of a highly propellant efficient electric propulsion system due to the nature of the mission. In this study, the space mission analysis for a simple on-orbit mission involving Hall thruster is conducted, which is life extension mission for geostationary orbit satellites. In order to analyze the mission, design space exploration for various Hall thruster design variable combinations is performed. The values of design variables and operational parameters of Hall thruster suitable for the mission are proposed through design space analysis and optimization, and mission performance is derived. In addition, the direction of further improvement for the current on-orbit mission analysis process and space mission analysis involving Hall thruster is reviewed.

• Progress in Medical Physics
• /
• v.21 no.2
• /
• pp.223-231
• /
• 2010

We have taken surveys about total 72 departments of radiation oncology which is performing the treatment with linear accelerator and brachytherapy unit in Korea. The survey was included the research about the linear accelerator, brachytherapy, Also, we surveyed the various performance (QA period, manpower, time) of quality control for understanding of efficiency. The survey results show that the QA test of daily and weekly are almost same comparing to USA and Europe but the QA performance of monthly and yearly in Korea are 15.5 which is less than USA and Europe recommended QA item number of 17 to 21. The manpower and QA time in Korea also lower than 50% of USA and Europe recommended because the manpower and QA time limitation in Korea. It will be expected that the manual of quality management in each clinic could be appropriately established when combining the present results with previously published AAPM TG-40 and other protocols.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2011.05a
• /
• pp.318-318
• /
• 2011

자연수를 가압(4~5기압)하면서 물과 공기의 비를 4:1~3:1로 혼합하면 수체 내 초미세기포(Diameter $3{\sim}10{\mu}m$)가 발생하는데 이를 산소용해수라 하며 수질정화시설 또는 양식장 등에 널리 사용되고 있다. 산소용해수의 특징은 기포의 비표면적이 넓고 10시간 이상 포화 농도를 유지하여 수체에 잔류하는 시간이 길기 때문에, 일반 산기석을 활용한 포기나 순산소 용해 등의 타 방법과 구별된다. 산소용해수의 산소전달효율은 기존 방법과 큰 차이를 보이기 때문에 실제 적용시에는 대상수를 이용하여 산소전달계수($K_{L}a$)를 사전에 산정할 필요가 있다. 본 연구에서는 한국건설기술 연구원의 안동 수자원 환경실험센터 내 실외형 콘크리트 사각반응수조에 산소용해장치 및 확산장치를 결합한 일체형 시스템을 적용시켜 2010년 9월~2011년 1월의 5개월간 결과를 분석, 본 장치의 $K_{L}a$를 산정 후 수질정화의 활용 면에서 검토하였다. $K_{L}a$의 산정에는 다양한 방법이 이용되나 용존 산소 농도의 제어에 한계가 있는 실외 대형실험장에 적합한 Lewis and Whitman의 Two-film 이론에 근거한 정상포기법을 적용하였다. 체적 $80m^3$의 수조 내에서 현장 유지용수를 대상으로 실험한 결과 산소전달계수는 $0.324\pm0.050$/min, 포화농도는 8.64 mg $O_2$/L, 도달시간은 11 /min이 산정되었으며, 이는 기존 산기석 포기의 산소전달계수 범위인 $0.105\pm0.019$ /min보다 약 3.1배 높은 결과를 보였다. 또한, 확산장치의 수류 순환 방향 및 정도를 검토하기 위하여 실험수조에서 1m단위로 격자를 구성한 후 초음파 유속계로 실측한 결과 0.0~2.5 m/s 의 평면적 유속범위를 도출하였다. 그리고 전체 순환을 고려했을 때 용존산소는 약 8시간 후 8.64 mg $O_2$/L 값에 도달하여 안정화 되었으며, 강한 수류순환과 산소용해수에 의해 하상에 존재하는 퇴적물들의 이송 및 산화촉진을 유도하였다. 이를 근거로 실험수조의 체적과 기준 가동시간인 8시간을 적용시켰을 때, 실험구 수질은 대조구와 비교하여 COD, T-N, T-P가 모두 25~35% 개선되었다. 이 결과는 여과공정 없이 단순 순환만을 고려한 물리적 수질정화 방법의 단독 활용 가능성을 나타내며, 기존 연구에서 나타난 SOD (Sediment oxygen demand) 저감 능력을 감안할 때 향후 폐쇄성 수역의 수질관리에도 효율적으로 활용할 수 있음을 시사한다.