• Title/Summary/Keyword: scale gains

Search Result 56, Processing Time 0.028 seconds

A Study on the Cost State of the Stow Net Fisheries. (연안안강망어업의 원가실태에 관한 연구)

  • 박정호
    • The Journal of Fisheries Business Administration
    • /
    • v.7 no.1
    • /
    • pp.27-41
    • /
    • 1976
  • The results analyzed of the actual state of the stow net fisheries based on the cost expended in 1975 areas follows; The total cost of this fisheries will be 1, 672, 238 won; the production cost, 1, 588, 060 won (95%) ; the material cost in proportion to total cost (100%)408, 480won (24.4%);the labour cost, 1, 006, 480 won (60.2%) ; the expenses, 173, 100won(10.4%)and the commission and the interest payment, 84, 178won(5%). As above the commission and the interest payment doesn't need to be paid much, but only production cost should be paid in case of small scale inshore fisheries. The cost per unit of caches (per Kg) becomes 12 won, the ratio cost of sales (83.4%), the ratio of profit, 16.%. According to the adove, in case of the powered vessel; it shows a tendency of spending too much expenses owing to excessive payment of oil. And in case of nonpowered vessels, it shows a tendency of spending less expenses but still get much gains, due to the fact that the commission and the interest payment are less, and none is paid for fuel procurement.

  • PDF

A new Dynamic Switching Function for Output feedback Variable Structure Control (출력궤환가변구조제어를 위한 동적스위칭함수의 제안과 응용)

  • 이기상;송명현;조상호
    • The Transactions of the Korean Institute of Electrical Engineers
    • /
    • v.40 no.7
    • /
    • pp.706-717
    • /
    • 1991
  • In order to remove the assumption of full state availability which is one of the major difficulties with the practical realization of variable structure control systems,a new switching function with a dynamic structure is proposed. And the control performances of the output feedback variable structure control systems with the dynamic switching function are evaluated through simulation studies. The proposed dynamic switching function is driven by small number of measured output and input variables while conventional static switching function requires full state information. Therefore, the proposition of the dynamic swiching function makes practical implementation of output feedback variable structure control scheme possible for the systems with unmeasurable state variables, high order systems and large scale systems that the conventional variable structure control schemes with static switching function cannot be applied. In the variable structure control systems with the dynamic switching function, desired control performance can be guaranteed by proper choice of design parameters such as poles of switching function dynamic equation and switching control gains even though small number of measured output and input variables are provided as shown in simulation resuls.

  • PDF

Effects of Channel Aging in Massive MIMO Systems

  • Truong, Kien T.;Heath, Robert W. Jr.
    • Journal of Communications and Networks
    • /
    • v.15 no.4
    • /
    • pp.338-351
    • /
    • 2013
  • Multiple-input multiple-output (MIMO) communication may provide high spectral efficiency through the deployment of a very large number of antenna elements at the base stations. The gains from massive MIMO communication come from the use of multi-user MIMO on the uplink and downlink, but with a large excess of antennas at the base station compared to the number of served users. Initial work on massive MIMO did not fully address several practical issues associated with its deployment. This paper considers the impact of channel aging on the performance of massive MIMO systems. The effects of channel variation are characterized as a function of different system parameters assuming a simple model for the channel time variations at the transmitter. Channel prediction is proposed to overcome channel aging effects. The analytical results on aging show how capacity is lost due to time variation in the channel. Numerical results in a multicell network show that massive MIMO works even with some channel variation and that channel prediction could partially overcome channel aging effects.

Design of Micro-Machining System for Micro/Meso Mechanical Component (Micro/Meso부품 대응형 마이크로 기계가공시스템 기술 연구)

  • Park J.K.;Kyung J.H.;Ro S.K.;Kim B.S.;Park J.H.
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • 2005.05a
    • /
    • pp.377-382
    • /
    • 2005
  • This paper describes the design of micro machine tools system for mechanical machining of micro/meso scale mechanical parts. The micro machining systems such as $\mu-Late$, $\mu-milling/drilling$ machine and $\mu-grinding$ machine are the basic elements constructing $\mu-factory$ which gains more attention recently because of increasing needs of mico and nano-parts in various industrial and medical area. A miniaturized 3-axis milling machine with VCM stage and air spindle and palm-top size micro-late are designed, and air bearing stage and stepwise linear motion system with PZT are studied for motion system. The micro cutting characteristics are investigated experimentally, and reconfigurable machine structures are also considered.

  • PDF

Effects of Nb Addition on Microstructure and Oxidation Behavior of Ti Alloy (Nb이 첨가된 Ti합금의 미세 조직 및 산화 거동)

  • 이도재;이광민;이경구;박범수;김수학;전충극;윤계림
    • Journal of the Korean institute of surface engineering
    • /
    • v.37 no.1
    • /
    • pp.58-63
    • /
    • 2004
  • The oxidation behavior of Ti-Nb alloys was studied in dry atmosphere. After vacuum arc melting and hot rolling treatment, Ti-Nb alloys were oxidized at $450^{\circ}C$$750^{\circ}C$. The oxidation behaviors between matrix and oxide scale were analyzed by SEM, XPS and XRD. Ti-Nb alloys had higher oxidation resistance than pure Ti at $750^{\circ}C$. XPS analysis of oxide film revealed that $TiO_2$ oxide was formed on the top of surface. The weight gains during the oxidation increase rapidly at temperature above $600^{\circ}C$ which obey the parabolic law.

Microstructures and Cyclic Oxidation Resistance of Aluminide Coatings for Inconel 600 (Inconel 600에 있어서 Al抗散浸透 被覆層의 微細組織과 耐反復酸化性)

  • Chung, In-Sang;Byun, Chang-Suk
    • Journal of the Korean institute of surface engineering
    • /
    • v.20 no.2
    • /
    • pp.60-73
    • /
    • 1987
  • For the purpose of improving the cyclic oxidation resistance of Ni-base superalloy, Inconel 600, aluminide coating methods are studied. The formation rate of aluminide coating layers is measured as a function of time and pack composition to find out the optimum coating condition. The evaluation of cyclic oxidation is established by the change in weight, the microphotography and EPMA of cross sectional area during $200^{\circ}C\;{\leftrightarrow}\;950^{\circ}C\;and\;200^{\circ}C\;{\leftrightarrow}\;1100^{\circ}C$, respectively. The thickness of coating layer and weight gains are parabolic behavior in propotion to time and Al contents. In pack of low aluminum contents, 2 wt%, however, weight gain is decreased when activator, $NH_4Cl$ is higher than 2 wt%. The cyclic oxidation resistance of the coating carried out at 1100$^{\circ}C$ are superior to those of the coating diffusion-treated after pack cementation at 800$^{\circ}C$. Aluminide oxide, which is formed in external scale, is barrier to the cyclic oxidation.

  • PDF

Comparison of Preferred Features in Spatial Composition for Shared Housing between Rural and Urban Elderly

  • Lee, Ji-Hye;Lee, Yeun-Sook
    • KIEAE Journal
    • /
    • v.15 no.1
    • /
    • pp.29-43
    • /
    • 2015
  • Shared housing for elderly people, where several elderly people live together, gains attention as a means to prevent the lonely death of elderly people and continuously maintain their social relations. The purpose of this study is to compare the characteristics planned through rural and urban areas-residing elderly people's participation in the shared housing spatial composition by area. This study conducted a small scale workshop panel method that targeted small group, but through which extensive information can be acquired, as a qualitative method. This study targeted 16 elderly people aged 65 and over living in rented apartments in rural and urban areas by dividing them two groups by area, namely into four groups. A total of 12 workshop sessions were held with three sessions at a time through a certain time interval. As a result of the study, the elderly people showed positive responses to the shared housing, irrelevant of area. As time went on, the workshop panel method's effect was revealed through consolidated positive attitude and agreement of different opinions. The shared housing for elderly people is valuable as a residential alternative for elderly people, and differentiated supply of the shared housing for elderly people, according to residential area's characteristics, is suggested.

Development and Identification of Pneumatic Excavator System (모형 공압굴삭기 시스템 구축)

  • Lee, Hong-Sun;Cheon, Se-Young;Lim, Tae-Hyeong;Kim, Sung-Su;Choi, Jeong-Ju;Yang, Soon-Young
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.16 no.3
    • /
    • pp.31-36
    • /
    • 2007
  • The excavator is complex machinery which has widely used in the construction site, deck of harbor and deep sea. The one of important issue of excavator system in recent is an automation of it in order to improve a working efficiency, a convenience working circumstance and work satisfaction. However, since there are large nonlinearities of control circuit, actuating cylinder, joiners of hydraulic units and changing loads etc., it is difficult to develope an automatic excavator system. Therefore, in this study, toy scale pneumatic excavator system is constructed and the remote control system is installed on it, before developing the automatic excavator system. In order to design the control system of the developed pneumatic excavator system, the transfer function is obtained using signal processing method and the controller gains of PID are decided based on CDM(coefficient diagram method). The obtained transfer function and the performance of the proposed control system is evaluated through experiments and computer simulation.

CORROSION BEHAVIOR OF NI-BASE ALLOYS IN SUPERCRITICAL WATER

  • Zhang, Qiang;Tang, Rui;Li, Cong;Luo, Xin;Long, Chongsheng;Yin, Kaiju
    • Nuclear Engineering and Technology
    • /
    • v.41 no.1
    • /
    • pp.107-112
    • /
    • 2009
  • Corrosion of nickel-base alloys (Hastelloy C-276, Inconel 625, and Inconel X-750) in $500^{\circ}C$, 25MPa supercritical water (with 10 wppb oxygen) was investigated to evaluate the suitability of these alloys for use in supercritical water reactors. Oxide scales formed on the samples were characterized by gravimetry, scanning electron microscopy/energy dispersive spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results indicate that, during the 1000h exposure, a dense spinel oxide layer, mainly consisting of a fine Cr-rich inner layer ($NiCr_{2}O_{4}$) underneath a coarse Fe-rich outer layer ($NiFe_{2}O_{4}$), developed on each alloy. Besides general corrosion, nodular corrosion occurred on alloy 625 possibly resulting from local attack of ${\gamma}$" clusters in the matrix. The mass gains for all alloys were small, while alloy X -750 exhibited the highest oxidation rate, probably due to the absence of Mo.

Development of Maglev Vehicle for Semiconductor Transport System in Small Scale (반도체 반송 시스템을 위한 축소형 자기부상 열차 시스템 개발)

  • Sung, So-Young;Choi, Jang-Young;Sung, Ho-Kyung;Cho, Han-Wook;Jang, Seok-Myung
    • Proceedings of the KIEE Conference
    • /
    • 2008.07a
    • /
    • pp.616-618
    • /
    • 2008
  • This paper propose nonlinear electromagnet suspension system model and defines electromagnet design specification of Maglev vehicle for transport system of semiconductor manufacturing line. The bandwidth of the acceleration sensor is defined and manufactured using i-mems technique acceleration sensor from this Nonlinear electromagnet suspension model. Through the simulation of non-linear model it was possible to compare the gain with the experiment to confirm the accuracy of the nonlinear suspension system. Till now mainly linear model has been used in many electromagnet suspension system, which results different gains in simulation and experiments. This more accurate non-linear model can be applied in many ways in designing electromagnet suspension systems.

  • PDF