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An Analysis of the Economic Effects of Unmanned Aerial Vehicle(UAV) Industry (무인항공기 산업의 경제적 파급효과 분석)

  • Kim, Kwang-Hoon;Won, Dong-Kyu;Yeo, Woon-Dong
    • The Journal of the Korea Contents Association
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    • v.18 no.2
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    • pp.216-230
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    • 2018
  • In this paper, we analyze the economic ripple effects of technology related to the unmanned aerial vehicle industry by applying industry association analysis. Specifically, the effects of employment creation, value added inducement, sensitivity coefficient, and influence coefficient can be calculated, and implications for the analysis result are presented. As a result, the employment inducement effect was confirmed to be 10.017 persons per 1 billion won of investment. The value added inducement effect was much higher than the other manufacturing industry average (employment inducement coefficient: 2.285, value added inducement coefficient: 0.581) when the 1 won budget was added, resulting in 0.9771 won added value. In the unmanned aerial vehicle industry, the coefficient of sensitivity, which means the front chain effect, is 0.7870, which is lower than the manufacturing average (sensitivity coefficient 1.125), and the coefficient of influence, which means the backward chain effect, is 1.161, which is higher than the manufacturing average (influence coefficient: 1.116). Therefore, it is classified as the final demand manufacturing industry. This means that the unmanned aerial vehicle industry is an industry that is less affected by economic fluctuations and can be interpreted as an industry with a greater economic impact than other sectors. Based on these data, it can be used to establish the R&D investment direction policy of the unmanned aerospace industry.

Forage Production and Utilization in Southern Area of China (중국 남방지구의 사초 생산과 이용)

  • Jiang, Y.Q.;Liu, J.X.;Zhou, W.D.;Huang, X.
    • Proceedings of the Korean Society of Grassland Science Conference
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    • 2002.09b
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    • pp.159-183
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    • 2002
  • China is the country with more people and more land, faced with the pressure of population growth and land decrement. The potential of developing animal husbandry by increasing feed grain per capita is less and less. "Planting forage to feed livestock" is a sustainable industry with grain-saying, high efficiency, good quality and safety, accorded with the conditions of China. First, the natural, social and economical condition in southern area of China was analyzed, and the characteristics of production and utilization of forage were introduced in this paper. The natural condition in southern area of China was well suited for forage production. Forage was mainly planted on famland. Main herbage cultivars were annual or hibernal annual. Most of forage was directly utilized by herbivorous animal and fish. Second, The present situation, developmental trend and existing problems of forage industrialization were reviewed. The level of forage industrialization was low with a bright future. At present, the chief existing problems were lack of herbage cultivars of good quality, backward equipment, lagged techniques and low level of mechanization in forage processing with a short time and so on. Finally, the situation of production and utilization of forage was summarized.

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Performance Evaluation of a Driving Power Transmission System for 50 kW Narrow Tractors

  • Hong, Soon-Jung;Ha, Jong-Kyou;Kim, Yong-Joo;Kabir, Md. Shaha Nur;Seo, Young Woo;Chung, Sun-Ok
    • Journal of Biosystems Engineering
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    • v.43 no.1
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    • pp.1-13
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    • 2018
  • Purpose: The development of compact tractors that can be used in dry fields, greenhouses, and orchards for pest control, weeding, transportation, and harvesting is necessary. The development and performance evaluation of power transmission units are very important when it comes to tractor development. This study evaluates the performance of a driving power transmission unit of a 50 kW multi-purpose narrow tractor. Methods: The performance of the transmission and forward-reverse clutch, which are the main components of the driving power transmission unit of multi-purpose narrow tractors, was evaluated herein. The transmission performance was evaluated in terms of power transmission efficiency, noise, and axle load, while the forward-reverse clutch performance was evaluated in terms of durability. The transmission's power transmission efficiency accounts for the measurement of transmission losses, which occur in the transmission's gear, bearing, and oil seal. The motor's power was input in the transmission's input shaft. The rotational speed and torque were measured in the final output shaft. The noise was measured at each speed level after installing a microphone on the left, right, and upper sides. The axle load test was performed through a continuous equilibrium load test, in which a constant load was continuously applied. The forward-reverse clutch performance was calculated using the engine torque to axle torque ratio with the assembled engine and transmission. Results: The loss of power in the transmission efficiency test of the driving power unit was 6.0-9.7 kW based on all gear steps. This loss of horsepower was equal to 11-18% of the input power (52 kW). The transmission efficiency of the driving power unit was 81.5-89.0%. The noise of the driving power unit was 50-57 dB at 800 rpm, 70-77 dB at 1600 rpm, and 76-83 dB at 2400 rpm. The axle load test verified that the input torque and axle revolutions were constant. The results of the forward-reverse clutch performance test revealed that hydraulic pressure and torque changes were stably maintained when moving forward or backward, and its operation met the hydraulic design standards. Conclusions: When comprehensively examined, these research results were similar to the main driving power transmission systems from USA and Japan in terms of performance. Based on these results, tractor prototypes are expected to be created and supplied to farmhouses after going through sufficient in-situ adaptability tests.

The Development of Postverbal Negation in Korean in a Korean-English Bilingual Child (한국어와 영어 두 언어를 동시에 습득하는 한국어린이의 한국어 후치부정어 습득에 대한 연구)

  • Kim, Myung-Sook
    • Korean Journal of Cognitive Science
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    • v.20 no.4
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    • pp.383-419
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    • 2009
  • This study investigates the developmental process of Korean postverbal negation in a Korean-English bilingual child. The purposes of this study are firstly to find both common and divergent paths in the development of Korean postverbal negation in terms of both syntactic development and pragmatic uses of postverbal negation; and secondly to investigate explanations for the special pattern of development observed. The data were collected from one bilingual child (R) who is simultaneously acquiring two languages, Korean and English over two years between the ages of 5;00 and 700 (years; months). The data collection was carried out in four periods in two different environments: Periods I and III in Australia, Periods II and IV in Korea. The development of postverbal negation showed that when R was in Australia, she employed both L1 and L2 learning mechanisms, while when she was in Korea, she employed L1 learning mechanisms. The results reveal that L1 and L2 mechanisms are not basically different because R shows both forward and backward developmental features in conjunction with the two different language environments: Korea and Australia.

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Semantic Inference System Using Backward Chaining (후방향 추론기법을 이용한 시멘틱 추론 시스템)

  • 함영경;박영택
    • Proceedings of the Korean Information Science Society Conference
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    • 2003.10a
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    • pp.97-99
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    • 2003
  • 대부분의 웹 문서들은 HTML이나 XML로 표현된 웹의 정보들은 Syntactic 구조를 기반으로 표현되기 때문에, 소프트웨어가 정보를 처리하는데 한계가 있다. HTML은 문서의 display안을 위한 tag기반의 문서 표현 방식이고, XML은 문서의 구조를 사람이 이해하기 쉽도록 제안된 표현 방식이기 때문이다. 따라서, HTML 및 XML로 표현된 정보들을 가지고 서비스를 제공하는 웹 에이전트들은 사용자들에게 의미있는 서비스를 제공하기 위해 오프라인 상에서 많은 수작업을 수행해야만 했다. 이와 같은 문제점을 극복하기 위해서 미국과 유럽에서는 시멘틱 웹에 대한 연구를 활발히 진행하고 있다. 시멘틱 웹은 기존의 웹과는 달리 소프트웨어가 이해하고 처리 할 수 있는 형태(machine processable)로 정보를 표현하기 때문에 오프라인 상에서 수행되던 많은 작업들을 에이전트가 이해하고 처리할 수 있게 되었다. 그러나. 온톨로지를 구축하는 과정에서도 필연적으로 정보의 31(Incorrect, incomplete, Inconsistence)가 나타나고, 서비스의 결과 또한 온톨로지에 의해 좌우된다는 단점이 있다. 본 논문에서 제안하는 후방향 추론기법을 이용한 추론엔진은 다음과 같은 시스템을 제안한다. 첫째. 시멘틱 웹을 이용함으로써 소프트웨어 에이전트의 자동화 시스템을 제안한다. 둘째 은톨로지 정보의 한계성을 극복하기 위해 규칙기반의 후방향 추론 기법을 사용하는 시멘틱 추론엔진을 제안한다. 본 논문에서 제안하는 후방향 추론기법을 이용한 시멘틱 추론시스템은 사용자의 질의를 입력받아. 온톨로지와 시멘틱 웹 문서의 정보를 이용하여 후방향 추론을 수행함으로써 웹 정보의 불완전성을 완화하고, 온톨로지의 영향력를 감소시킴으로써 웹 서비스의 질을 향상시키는데 목적이 있다.RED에 비해 향상된 성능을 보여주었다.웍스 네트워크상의 다양한 디바이스들간의 네트워크 다양화와 분산화 기능을 얻을 수 있었고, 기존의 고가의 해외 솔루션인 Echelon사의 LonMaker 소프트웨어를 사용하지 않고도 국내의 순수 솔루션인 리눅스 기반의 LonWare 3.0 다중 바인딩 기능을 통해 저 비용으로 홈 네트워크 구성 관리 서버 시스템 개발에 대한 비용을 줄일 수 있다. 기대된다.e 함량이 대체로 높게 나타났다. 점미가 수가용성분에서 goucose대비 용출함량이 고르게 나타나는 경향을 보였고 흑미는 알칼리가용분에서 glucose가 상당량(0.68%) 포함되고 있음을 보여주었고 arabinose(0.68%), xylose(0.05%)도 다른 종류에 비해서 다량 함유한 것으로 나타났다. 흑미는 총식이섬유 함량이 높고 pectic substances, hemicellulose, uronic acid 함량이 높아서 콜레스테롤 저하 등의 효과가 기대되며 고섬유식품으로서 조리 특성 연구가 필요한 것으로 사료된다.리하였다. 얻어진 소견(所見)은 다음과 같았다. 1. 모년령(母年齡), 임신회수(姙娠回數), 임신기간(姙娠其間), 출산시체중등(出産時體重等)의 제요인(諸要因)은 주산기사망(周産基死亡)에 대(對)하여 통계적(統計的)으로 유의(有意)한 영향을 미치고 있어 $25{\sim}29$세(歲)의 연령군에서, 2번째 임신과 2번째의 출산에서 그리고 만삭의 임신 기간에, 출산시체중(出産時體重) $3.50{\sim}3.99kg$사이의 아이에서 그 주산기사망률(周産基死亡率)이 각각 가장 낮았다. 2. 사산(死産)과 초생아사망(初生兒死亡)을 구분(區分)하여 고려해 볼때 사산(死産)은 모성(母性)의 임신력(姙娠歷)과 매우 밀접한 관련이 있는 것으

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Size Distributions of Trace Elements in Airborn Particulates Collected using Drum impactor at Gosan, Jeju Island : Measurements in Springtime 2002 (DRUM impactor를 이용한 대기 입자상 물질 중 원소성분의 입경분포 특성 : 제주도 고산지역의 2002년 봄철 (3.29-5.30) 측정 연구)

  • 한진석;문광주;류성윤;안준영;공부주;홍유덕;김영준
    • Journal of Korean Society for Atmospheric Environment
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    • v.20 no.4
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    • pp.555-569
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    • 2004
  • Size -segregated measurements of aerosol composition using 8-stage DRUM impactor are used to determine the transport of natural and anthropogenic aerosols at Gosan site from 29 March to 30 May in 2002. Separation of ambient aerosols by DRUM impactor offers many Advantages over other standard filtration techniques. Some of the most important advantages are the ability to segregate into details by particle tire, to better preserve chemical integrity since the air stream doesn't pars through the deposit, to collect samples as a function of time, and to have a wide variety of impaction surfaces available to match analytical needs. Although the transport of Yellow sand is a well-known phenomenon in springtime, the result of measurement shows that not only soil dust but also anthropogenic aerosols, including sulfur, enriched trace metals such as Pb, Ni, Zn. Cu, Cr, As, Se, Br, are transported to Gosan in springtime. This study combines the size- and time-resolved aerosol composition measurements with isentropic, backward air-mass trajectories in order to identify some potential source regions of anthropogenic aerosols. As a result, during the NYS period, the average concentration of PM$_{10}$ was 46$\mu\textrm{g}$/㎥, Si, Al. S, Fe, Cl, K, Ca were higher than 1,000 ng/㎥ and Ti was about 100 ng/㎥. The concentrations of Zn, Mn, Cu. Pb, Br, Rb, V, Cr, Ni. At, Se ranged between 1 and 70 ng/㎥. More than 50% typical soil elements, tuck as Al, Si, Fe, Cd. Ti, Cr, Cu, Br. were distributed in a coarse particle range(5.0-12${\mu}{\textrm}{m}$). In other hand, anthropogenic pollutants, luck as S, N, Vi, were mainly distributed in a fine particle range (0.09-0.56${\mu}{\textrm}{m}$). During the YS period, PM$_{10}$ increased about 8 times than NYS period, and main soil elements, such as Al, Si, S, K, V, Mn, Fe also doubled in coarse particle range (1.15-12${\mu}{\textrm}{m}$). But Zn, As, Pb, Cu and Se, which distributed in the time aerosols (0.09-0.56${\mu}{\textrm}{m}$), were on the same level with or decreased than NYS period. Finally. except the YS Period, coarse particles (2.5-12${\mu}{\textrm}{m}$) are inferred to be influenced by soil, coal combustion, waste incineration, ferrous and nonferrous sources through similar pathways with Yellow Sand. But fine particles have different sources, such as coal combustion, gasoline vehicle, biomass burning, oil or coal combustion, nonferrous and ferrous metal sources, which are transported from China, Korea peninsula and local sources.ces.

Time-series Variation of Atmospheric Radon Concentrations at Gosan Site, Jeju Island (제주도 고산측정소의 대기 라돈농도 시계열 변화)

  • Ko, Hee-Jung;Sin, Seung-Hee;Hu, Chul-Goo;Kim, Won-Hyung;Kang, Chang-Hee;Kang, Dong-Hun;Chambers, Scott
    • Journal of Korean Society for Atmospheric Environment
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    • v.29 no.1
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    • pp.86-96
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    • 2013
  • The realtime monitoring of radon ($^{222}Rn$) concentrations has been carried out from Gosan site, Jeju Island for three years of 2006~2008, in order to evaluate the background level and timely variational characteristics of atmospheric radon. The mean concentration of radon measured during the studying period was $2965mBq/m^3$ with its annual mean values in the range of $2768{\sim}3124mBq/m^3$. The relative ordering of the seasonal mean concentrations was seemed to vary such as winter ($3578mBq/m^3$) > fall ($3351mBq/m^3$) > spring ($2832mBq/m^3$) > summer ($2073mBq/m^3$). The monthly mean concentrations were in the order of Jan>Feb>Oct>Nov>Dec>Mar> Sep>Apr>May>Jun>Aug>Jul, so that the highest January value ($3713mBq/m^3$) exceeded almost twice as the July minimum ($1946mBq/m^3$). The hourly concentrations in a day showed the highest level ($3356mBq/m^3$) at around 7 a.m., increasing during nighttime, while reaching the lowest ($2574mBq/m^3$) at around 3 p.m. From the backward trajectory analysis for a continental fetch of radon, the high concentrations (10%) of radon matched with the air mass moving from the Asia continent to Jeju area. In contrast, the low concentrations (10%) of radon were generally correlated with the air mass of the North Pacific Ocean. In comparison by sectional inflow pathways of air mass, the radon concentrations were relatively high from the north China and the Korean peninsula.

A study of Assessment for Internal Inundation Vulnerability in Urban Area using SWMM (SWMM을 이용한 도시지역 내수침수 취약성 평가)

  • Shon, Tae-Seok;Kang, Dong-Ho;Jang, Jong-Kyung;Shin, Hyun-Suk
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.4
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    • pp.105-117
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    • 2010
  • The topographical depressions in urban areas, the lack in drainage capability, sewage backward flow, road drainage, etc. cause internal inundation, and the increase in rainfall resulting from recent climate change, the rapid urbanization accompanied by economic development and population growth, and the increase in an impervious area in urban areas deteriorate the risk of internal inundation in the urban areas. In this study, the vulnerability of internal inundation in urban areas is analyzed and SWMM model is applied into Oncheoncheon watershed, which represents urban river of Busan, as a target basin. Based on the results, the representative storm sewers in individual sub-catchments is selected and the risk of vulnerability to internal inundation due to rainfall in urban streams is analyzed. In order to analyze the risk and vulnerability of internal inundation, capacity is applied as an index indicating the volume of a storm sewer in the SWMM model, and the risk of internal inundation is into 4 steps. For the analysis on the risk of internal inundation, simulation results by using a SMMM model are compared with the actual inundation areas resulting from localized heavy rain on July 7, 2009 at Busan and comparison results are analyzed to prove the validity of the designed model. Accordingly, probabilistic rainfall at Busan was input to the model for each frequency (10, 20, 50, 100 years) and duration (6, 12, 18, 24hr) at Busan. In this study, it suggests that the findings can be used to preliminarily alarm the possibility of internal inundation and selecting the vulnerable zones in urban areas.

Design of spectrum spreading technique applied to DVB-S2

  • Kim, Pan-Soo;Chang, Dae-Ig;Lee, Ho-Jin
    • Journal of Satellite, Information and Communications
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    • v.2 no.2
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    • pp.22-28
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    • 2007
  • Spectrum spreading, in its general form, can be conceived as an artificial expansion of the signal bandwidth with respect to the minimum Nyquist band required to transmit the desired information. Spreading can be functional to several objectives, including resilience to interference and jammers and reduction of power spectral density levels. In the paper, signal spreading is manly used for increasing the received energy, thus satisfying link budget constraints, for terminals with low aperture antennas, without increasing the transmitted EIRP. As a matter of fact, in many mobile scenarios, even when MODCOD configurations with very low spectral efficiency (i.e. QPSK-1/4) in DVB-S2 standard, are used, the link budget cannot be closed. Spectrum spreading has been recently proposed as a technique to improve system performance without introducing additional MODCOD configurations under the constraint of fixed power spectrum density level at the transmitter side. To this aim, the design of spectrum spreading techniques shall keep into consideration requirements such as spectrum mask, physical layer performance, link budget, hardware reuse, robustness, complexity, and backward compliance with existing commercial equipments. The proposed implementation allows to fully reuse the standard DVB-S2 circuitry and is inserted as an 'inner layer' in the standard DVB-S2 chain.

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Barrier Option Pricing with Binomial Trees Applying Generalized Catalan Numbers (이항분포모형에 일반화된 카탈란 수를 적용한 배리어 옵션의 가격 산정)

  • Choi, Seung-il
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.12
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    • pp.226-231
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    • 2016
  • Binomial trees are used to price barrier options. Since barrier options are path dependent, option values of each node are calculated from binomial trees using backward induction. We use generalized Catalan numbers to determine the number of cases not reaching a barrier. We will generalize Catalan numbers by imposing upper and lower bounds. Reaching a barrier in binomial trees is determined by the difference between the number of up states and down states. If we count the cases that the differences between the up states and down states remain in a specific range, the probability of not reaching a barrier is obtained at a final node of the tree. With probabilities and option values at the final nodes of the tree, option prices are computable by discounting the expected option value at expiry. Without calculating option values in the middle nodes of binomial trees, option prices are computable only with final option values. We can obtain a probability distribution of exercising an option at expiry. Generalized Catalan numbers are expected to be applicable in many other areas.