• Title/Summary/Keyword: ports

Search Result 1,840, Processing Time 0.025 seconds

Design of Compact and Broadband Quasi-Yagi Antenna Using Balance Analysis of the Balun (발룬의 평형도 해석을 이용한 소형화된 광대역 Quasi-Yagi 안테나 설계)

  • Woo, Dong Sik;Kim, In-Bok;Kim, Young-Gon;Kim, Kang Wook
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.24 no.1
    • /
    • pp.27-35
    • /
    • 2013
  • In this paper, a compact, broadband quasi-Yagi antenna utilizing balance analysis of the ultra-wideband microstrip-to-coplanar stripline(MS-to-CPS) balun is proposed. The antenna size was reduced by removing the reflector on bottom layer and ground plane is used as a reflector. A planar balun that transforms from microstrip(MS) to balanced coplanar stripline(CPS) is characterized in the amplitude and phase imbalances at CPS output ports are investigated and discussed. As compared with the conventional balun, the proposed MS-to-CPS balun demonstrated very wideband performance from 7 to over 20 GHz. From the simulation study, amplitude and phase imbalances are within 1 dB and ${\pm}5^{\circ}$, respectively. The implemented antenna provides very wide bandwidth from 6.9 to 15.1 GHz(74.5 %). The gain of the antenna is from 3.7 to 5.5 dBi, the front-to-back ratio is more than 10 dB, and the nominal radiation efficiency is about 94 %.

A Study on the Detection of the Rain Using Open-Ended Coaxial Cavity Resonator (한쪽 면이 열린 동축 공동 공진기를 이용한 빗물 감지에 관한 연구)

  • Lee, Yun-Min;Kim, Jin-Kuk;Hur, Jung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.24 no.9
    • /
    • pp.944-950
    • /
    • 2013
  • This paper is a study of a rain sensor using an open-ended coaxial cavity resonator which senses the amount of rain drops linearly. It shows that it will be used as a sensor to sense the amount of rain dropped on the windshield of an automobile based on the principle of varied resonant frequency and the loss according to the amount and characteristics of an dielectric lied on the open side of a resonator. The input and output ports are built in the both sides of the resonator and the input and output coupling probes are formed like 'ㄱ' shape. The response of rain drops were simulated by the radius of inner conductor of 2 mm, 5 mm, and 10 mm respectively and it showed that the raindrop was sensed most linearly and sensitively when the radius of inner conductor is 5 mm, We have measured that the resonant frequency have varied from 3.55 GHz to 3 GHz and the Q value have varied from 42.38 to 24.3 according to the variation of rain drop amount on the fabricated resonator. Therefore, it shows that the designed resonator can be applied as a rain sensor that measures the amount of rain drops linearly by using the resonant frequency as a measurement parameter.

A Study on Efficient Cell Queueing and Scheduling Algorithms for Multimedia Support in ATM Switches (ATM 교환기에서 멀티미디어 트래픽 지원을 위한 효율적인 셀 큐잉 및 스케줄링 알고리즘에 관한 연구)

  • Park, Jin-Su;Lee, Sung-Won;Kim, Young-Beom
    • Journal of IKEEE
    • /
    • v.5 no.1 s.8
    • /
    • pp.100-110
    • /
    • 2001
  • In this paper, we investigated several buffer management schemes for the design of shared-memory type ATM switches, which can enhance the utilization of switch resources and can support quality-of-service (QoS) functionalities. Our results show that dynamic threshold (DT) scheme demonstrate a moderate degree of robustness close to pushout(PO) scheme, which is known to be impractical in the perspective of hardware implementation, under various traffic conditions such as traffic loads, burstyness of incoming traffic, and load non-uniformity across output ports. Next, we considered buffer management strategies to support QoS functions, which utilize parameter values obtained via connection admission control (CAC) procedures to set tile threshold values. Through simulations, we showed that the buffer management schemes adopted behave well in the sense that they can protect regulated traffic from unregulated cell traffic in allocating buffer space. In particular, it was observed that dynamic partitioning is superior in terms of QoS support than virtual partitioning.

  • PDF

A Systematic Approach to Port related Problems An Analysis on the Actual Condition of physical Distribution System of Pusan port (항만관련문제의 시스템적 고찰 부산항 물류시스템의 실태분석)

  • Lee Cheol-Yeong;Moon Seong-Hyeok
    • Journal of Korean Port Research
    • /
    • v.2 no.1
    • /
    • pp.7-28
    • /
    • 1988
  • From the viewpoint of physical distribution, the port transport process can be regarded as a system which consists of various subsystems such as navigational aids, quay handling, transfer, storage, information If management, and co-ordination with inland transport. The handling productivity of this system is determined by the production level of the least productive subsystem. So, a productivity analysis on the flow of cargoes through each subsystem should be made in order to achieve efficient port operation. The purpose of this paper is to analyze the productivity of each subsystem in Pusan port, and to bring forward problems and finally to draw up plans for their betterment. Analyzed results on the productivity of each subsystem are as follows, i) It is known that the number of tugs with low HP should be increased by a few, the number of tugs with medium HP is appropriate, and the number of tugs with high HP is in excess of that necessary. ii ) In the case of container cargoes, it is found that the transfer and storage systems in BCTOC have the lowest handling capability, with a rate of $115\%$, leading to bottle-necks in the port transport system, while the handling rate of the storage and quay handling systems in general piers is in excess of the inherent capability. iii) In the case of the principal seaborne cargoes passing through general piers, there is found to be a remarkable bottle-neck in the storage system. In the light of these findings, both the extension of storage capability and the extension of handling productivity are urgently required to meet the needs of port users. Therefore, iv) As a short-term plan, it is proposed that many measures such as the reduction of free time, the efficient application of ODCY, etc must be brought in and v) In the long-trun, even though the handling capability will accommodate an additional 960,000 TEU in 1991, the scheduled completion date of the third development plan of Pusan port, insufficiency of handling facilities in the container terminal is still expected and concrete countermeasures will ultimately have to be taken for the port's harmonious operation. In particular, the problem of co-ordination with inland transport and urban traffic should be seriously examined together in the establishment of the Pusan port development. As a method of solving this, vi) It is suggested that Pusan port (North port) should be converted into an exclusive container ternimal and overall distribution systems to the other ports for treating general cargoes must be established. vii) And finally, it is also proposed that the arrival time (cut-off time) of influx cargoes for exports such as general merchandise and steel product should be limited, with a view to securing cargoes suitable for the operational capability of BCTOC.

  • PDF

A Study on Application Plan LTE Wireless Network in the Container Terminal Yard (컨테이너터미널 장치장에서 무선네트워크 LTE 적용방안에 관한 연구)

  • Cha, Sang-Hyun;Noh, Chang-Kyun
    • Journal of Navigation and Port Research
    • /
    • v.40 no.1
    • /
    • pp.43-50
    • /
    • 2016
  • Amid of the logistics hub center competition is going to intensifying between the world major port, it is essential to pre-occupied the base in the logistics hub world take advantage of advanced technology of logistics equipment than other ports. In existing container terminal, when container moves the terminal use the omnidirectional and directional antenna in order to exchange data information on the basis of 802.11 wireless network system. Case of loading height of exceeding, the blind sport will occur and a limited frequency channel can't help using in the area. A limited frequency channel usage and nested areas happen to use the closed terminal, it has a great influence to operate the terminal working. In this paper, LTE network is configured provided by the specified company ('L' Corp,.Ltd) and terminal data extracted through LBO (Local Breakout) in the cell site which is configured directly with container terminal operation server. Using this method, container terminal yard equipment operate without overlapping arises with uninterrupted data presented for ways to efficiently. I would suggest both the existing wireless AP LAN configuration of container terminal and new LTE system and applied to the real yard operating devices situations. Through these methods presented comparative the existing network traffic with new constructed LTE configuration. I admired to suggest that wireless network LTE introduction is fundamental factors to get rid of the blind spot, the problem of limited frequency channel and overlapping arises. These essential points can be a continual improving terminal services and more efficient terminal operational management.

Comparison and Analysis on Risk Assessment Models of Coastal Waters considering Human Factors (인적요인을 고려한 연안해역 위험도 평가모델 비교·분석)

  • Kim, In-Chul;An, Kwang
    • Journal of Navigation and Port Research
    • /
    • v.40 no.1
    • /
    • pp.27-34
    • /
    • 2016
  • For the prevention of marine casualties, international bodies have mainly focused on strengthening ship's stability and design, maritime education and training, and improving maritime traffic environment. Statistics analysis on marine casualties showed that most of casualties occurred in coastal waters, especially by human elements. In order to review the conformity of existing prevention measures with the result of the statistics analysis, the IMO's SHELL model was applied to the established measures. As a result, ergonomic approaches were needed for the prevention of human errors in coastal waters, so that the priority should be given to the interface between ship's operator and navigational environment. For this study, Rasmussen's SRK pyramid, which showed decision making mechanism of human, and the US Coast Guard's investigation manual on marine casualties concerning the collapse of safe maritime transportation system were reviewed, and the merits and demerits within the risk assessment tools such as IWRAP, PAWSA, ES model, PARK model, and NURI model were also studied. Although the effectiveness of the existing risk assessment models was proved in ports and approaching channels, it is concluded that the need of new models for converting Korean seafarers' qualitative risk to quantitative risk was proposed so as to print hazard maps which make seafarers instinctively recognize comparative hazard levels of coastal waters.

A Study on the Marketing System Construction and Merchandising of Tongyoung Marine Ranching (통영바다목장의 유통체제 구축과 상품화계획에 관한 연구)

  • 강종호;류정곤
    • The Journal of Fisheries Business Administration
    • /
    • v.34 no.2
    • /
    • pp.91-107
    • /
    • 2003
  • Distribution of fish products from Tongyoung Marine ranching can be classified by three routes such as street-stall, live fish transportation vehicles, and wholesale markets neighboring unloading ports. These methods of distribution, however, have been restricted by limited distribution right, difficulties to differentiate fish prices from other surfaces, simple marketing channels. The ratio of cultured live fish circulated in market is increasing while naturally caught live fish is decreasing and the fresh fish shows a little of increasing rate. Consumers purchasing routes mainly depend on the live fish transportation merchants. For fresh fish traditional market plays an important role in trade. Convenience for consumers and quality of products are main factors in making decision of purchases. Bargaining power, however, belongs to the live fish transportation merchants. The demand of special markets for live fish was very strong, and the convenience and quality are relatively important required factors. Catch from Tongyoung Marine ranching has very good reputation as the possibility of being a good brand. Expecting possibility of quality differentiation was higher than price differentiation specially. The possible conclusion of a contract of a supply was suspicious however. Preliminary quality evaluation revealed that the catch is better than the cultured but worse than naturally grown fish. A merchandising is to be in a better position in the formation of prices by giving $\ulcorner$brand image$\lrcorner$ to potential consumers. The target markets are retail stores such as restaurants for raw fish and final consumers. The staple markets are retail stores. Possible items of products are live fish, fresh fish for cook, and fresh fish for raw fish. It is necessary for the catch to be informed as new functional products that have been improved in safety and quality, since the product positioning is similar but not well known to consumers. To secure a brand it is required to register a trademark, eco-label product design or packing, use real name in tranction, introduce recall system, and put label. Price higher than naturally grown live fish should be targeted. Establishing broad distribution channel, wholesale market, franchise are required. To secure enough catch and control shipment of products facilities of containing live fish are necessary. Instead of dealing with live fish only, it would be better to. sell fresh fish and live fish simultaneous. Strategically promotion focuses on advertisement of Marin ranching at first and then focuses on the catch from the marine ranching.

  • PDF

A Study of the Fluidic Characteristics of High-Pressure Fuel Pumps for GDI Engines (GDI 고압펌프의 유동특성에 관한 연구)

  • Lee, Sangjin;Noh, Yoojeong;Liu, Hao;Lee, Jae-Cheon;Shin, Yongnam;Park, Yongduk;Kang, Myungkweon
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.39 no.5
    • /
    • pp.455-461
    • /
    • 2015
  • A high-pressure fuel pump is a key component in a gasoline direct injection (GDI) engine; thus, understanding its flow characteristics is essential for improving the engine power and fuel efficiency. In this study, AMESim, which is a hydraulic analysis program, was used to analyze the performance of the high-pressure fuel pump. However, since AMESim uses a one-dimensional model for the system analysis, it does not accurately analyze the complicated flow characteristics. Thus, Fluent, computational fluid dynamics (CFD) software, was used to calculate the flow rates and net forces at the intake and discharge ports of the high-pressure fuel pump where turbulent flow occurs. The CFD analysis results for various pressure conditions and valve lifts were used as look-up tables for the AMEsim model. The CFD analysis results complemented the AMEsim results, and thus, improved the accuracy of the performance analysis results for the high-pressure fuel pump.

A study on Regional Economic Effects of the logistics complex in Incheon New Port (인천신항 배후물류단지의 지역경제 파급효과 연구)

  • Ma, Moon-Shik;Yoo, Hong-Sung;Kim, Byung-Il
    • Journal of Korea Port Economic Association
    • /
    • v.25 no.4
    • /
    • pp.83-106
    • /
    • 2009
  • This study estimated the regional economic effects by development of the logistics complex in Incheon New Port, applying the regional Input-Output tables in Incheon. And thereby, we tried to find some strategic implications on the priority to induce more effective industries for activated operation of the logistics complex in ports. According to the results, development of Incheon New Port will generate 2,579 billion KRWs(2.2 billion USDs) of production and 1,783 KRWs(1.5 billion USDs) of value-added annually. And we expect it to induce 38.8 thousand jobs, which is over the national average on the input-output table. By the business type, port logistics industry will contribute to develop regional economy more than any other ones in Incheon. We suggest business firms in port logistics industry to be induced to the logistics complex in Incheon New Port strategically. Until now, development of the logistics complex in Incheon New Port are planned to be postponed to 2015 when construction of the berth facilities, the access sea routes and the hinterland highways are completed. We suggest to invest more public fund, to induce the private capital, and then, to develop the logistics complex in Incheon New Port earlier in an appropriate scale.

  • PDF

A Brief Efficiency Measurement Way for the Korean Container Terminals Using Stochastic Frontier Analysis (확률프론티어분석을 통한 국내컨테이너 터미널의 효율성 측정방법 소고)

  • Park, Ro-Kyung
    • Journal of Korea Port Economic Association
    • /
    • v.26 no.4
    • /
    • pp.63-87
    • /
    • 2010
  • The purpose of this paper is to measure the efficiency of Korean container terminals by using SFA(Stochastic Frontier Analysis). Inputs[Number of Employee, Quay Length, Container Terminal Area, Number of Gantry Crane], and output[TEU] are used for 3 years(2002,2003, and 2004) for 8 Korean container terminals by applying both SFA and DEA models. Empirical main results are as follows: First, Null hypothesis that technical inefficiency is not existed is rejected and in the trasnslog model, the estimate is significant. Second, time-series models show the significant results. Third, average technical efficiency of Korean container terminals are 73.49% in Cobb-Douglas model, and 79.04% in translog model. Fourth, to enhance the technical efficiency, Korean container terminals should increase the handling amount of TEUs. Fifth, both SFA and DEA models have the high Spearman ranking of correlation coefficients(84.45%). The main policy implication based on the findings of this study is that the manager of port investment and management of Ministry of Land, Transport and Maritime Affairs in Korea should introduce the SFA with DEA models for measuring the efficiency of Korean ports and terminals.


(34141) Korea Institute of Science and Technology Information, 245, Daehak-ro, Yuseong-gu, Daejeon
Copyright (C) KISTI. All Rights Reserved.