• Title/Summary/Keyword: Six-Port

Search Result 167, Processing Time 0.026 seconds

Predictive Control for a Fin Stabilizer

  • Yoon, Hyeon-Kyu;Lee, Gyeong-Joong;Fang, Tae-Hyun
    • Journal of Navigation and Port Research
    • /
    • v.31 no.7
    • /
    • pp.597-603
    • /
    • 2007
  • A predictive controller can solve a control problem related to a disturbance-dominant system such as roll stabilization of a ship in waves. In this paper, a predictive controller is developed for a fin stabilizer. Future wave-induced moment is modeled simply using two typical regular wave components for which six parameters are identified by the recursive Fourier transform and the least squares method using the past time series of the roll motion. After predicting the future wave-induced moment, optimal control theory is applied to discover the most effective command fin angle that will stabilize the roll motion. In the results, wave prediction performance is investigated, and the effectiveness of the predictive controller is compared to a conventional PD controller.

Factors Affecting Stock Beta Variations of Korean Listed Shipping Companies

  • Deog-Heon Park;Chi-Yeol Kim
    • Journal of Navigation and Port Research
    • /
    • v.47 no.2
    • /
    • pp.100-105
    • /
    • 2023
  • This study investigated determinants of stock betas of shipping companies in Korea. Beta is a measurement of sensitivity of an individual stock to the movement of the whole stock market. It is widely accepted that stock betas are not constant, but time-varying, which implies that they are affected by other factors. In this regard, this study examined betas of six shipping companies listed on the Korea Exchange for the period of 2000-2021 and their relationship with financial leverage, operating leverage, and cyclicality in the shipping market. Empirical analysis showed that betas of Korean shipping companies were positively associated with financial and operating leverages but negatively with cyclicality.

Nonlinear Finite Element Model for Tidal Analysis(II) -Model Application (조석유동 해석을 위한 비선형 유한요소 모형(II) -모형의 적용-)

  • 나정우;권순국
    • Magazine of the Korean Society of Agricultural Engineers
    • /
    • v.37 no.1
    • /
    • pp.37-48
    • /
    • 1995
  • The TIDE, nonlinear finite element model for the simulation of tidal analysis in a shal- low ooastal area was tested for its applicability at the Saemankeum day. Calibration of the TIDE model has been carried out using the six observed field data collected at five locations within the region for tidal velocity. Verification tests have been done using the six observed field data and four data o- tained from the hydraulic model test for the tidal velocity and elevation. Since the simula- tion results for the tidal elevation at Kunsan outer port by the TIDE model are well agreed with the results from the tidal table for one month, it is proved that the TIDE model may be used effectively to predict the tidal movement in the Saemankeum bay for a longer period.

  • PDF

A Study on the Advance Transportation System for Inter Terminal Transshipment: Focused on the Busan New Port (타부두 환적화물에 적합한 운송수단에 관한 연구;부산항 신항을 중심으로)

  • Jo, Mi-Ji;Lee, Seung-Pil;Kim, Hwan-Seong
    • Journal of Navigation and Port Research
    • /
    • v.44 no.4
    • /
    • pp.298-304
    • /
    • 2020
  • The purpose of this study was to identify evaluation factors and analyze the relative importance among factors to select a suitable transportation method for transferring the increasing amount of transshipment at multiple terminals at the Busan new port. To accomplish this, the evaluation factors were selected through a literature survey and brainstorming of a group of experts associated with the port operation, and were classified into five major factors and 15 middle factors. The evaluation factors classified hierarchically were surveyed relative to workers in organizations such as shipping companies, port corporations, container terminals, and related ministries. The importance of each factor was calculated using the hierarchical analysis process (AHP). As a result of the importance analysis, priority was assigned in order of safety, productivity, investment efficiency, operational efficiency, and policy conformity. Through this, it was necessary to select a suitable transportation method for the transshipment cargo in terminals while focusing on the cargo and terminal security and preventing accidents. As a result of calculating from six ITT transportation candidates, the priority was determined in order of monorail, Autocon, and so on as ITT transportation suitable for the Busan new port..

A Study on Estimating Air Pullution in the Port of Incheon (인천항의 대기오염물질 배출량 산정 연구)

  • Lee, Jeong-Uk;Lee, Hyang-Suk
    • Journal of Korea Port Economic Association
    • /
    • v.37 no.1
    • /
    • pp.143-157
    • /
    • 2021
  • International organizations such as the World Health Organization, the Organization for Economic Development and Cooperation, and major developed countries recognize the seriousness of air pollution. International organizations such as the International Maritime Organization have also implemented various regulations to reduce air pollution from ships. In line with this international trend, the government has also enacted a special law on improving air quality in port areas, and is making efforts to reduce air pollution caused by ports. The purpose of the Special Act is to implement comprehensive policies to improve air quality in port areas. This study sought to identify the emissions of each source of air pollutants originating from the port and prepare basic data on setting the policy priorities. To this end, the analysis was conducted in six categories: ships, vehicles, loading and unloading equipment, railways, unloading/wild ash dust, road ash dust, and the methodology presented by the European Environment Agency(EEA) and the United States Environmental Protection Agency(EPA). The pollutants subject to analysis were analyzed for carbon monoxide(CO), nitrogen oxides (NOX), sulfur oxides(SOX), total airborne materials(TSP), particulate matter(PM10, PM2.5), and ammonia(NH3). The analysis showed a total of 7,122 tons of emissions. By substance, NOX accounted for the largest portion of 5,084 tons, followed by CO (984 tons), SOX (530 tons), and TSP (335 tons). By source of emissions, ships accounted for the largest portion with 4,107 tons, followed by vehicles with 2,622 tons, showing high emissions. This proved to be the main cause of port air pollution, with 57.6% and 36.8% of total emissions, respectively, suggesting the need for countermeasures against these sources.

A Study on the Relative Operational Efficiency of Foreign Port Transportation Industry (외항운송업의 상대적 운영효율성 분석)

  • Kang, Da-Yeon;Lee, Ki-Se
    • The Journal of the Korea Contents Association
    • /
    • v.21 no.4
    • /
    • pp.88-95
    • /
    • 2021
  • In Korea, which achieved economic growth due to export industries, the economic importance of the foreign port transportation industry is very great. The government took the initiative in fostering the foreign port transportation industry, and as a result, it developed into one of the top 10 foreign port transport countries in the world. However, due to the poor management of the small and medium-sized foreign port transport business and the trade dispute between countries, the foreign port transportation industry has faced a long-term invasion. Therefore, in order for these companies to recover again, they will, among other things, have to reorganize their operational inefficiency to carry out efficient production activities. In this study, we want to analyze the management efficiency of the top 10% companies in the unlisted domestic outbound shipping industry, present the project value of inefficient enterprises, and confirm the reference collection of companies that may be subject to benchmarking. For this purpose, a total of 10 foreign port transportation industry were analysed for efficiency and scale profitability (RTS) of the CCR and BCC models. The analysis showed that there were a total of six entities with BCC efficiency and five entities with CCR efficiency. In addition, there were a total of five entities with both BCC and CCR efficiency.

Realization of Multi-Channel Active Filters by Using Operational Amplifiers (연산 증폭기를 사용한 다중 챈넬능동휠타의 구현)

  • Chung Duk Kim
    • 전기의세계
    • /
    • v.24 no.4
    • /
    • pp.80-82
    • /
    • 1975
  • This paper presents a synthesis procedure of multi-channel active filters, which realizes an arbitrary N*N matrix of real rational functions in the complex variable s as a voltage transfer matrix. The resultant network reveals a transformerless grounded active RC(2N+1)-terminal network. The active network is consisted of six 2N-port RC networks with 2N single-ended operational amplifiers.

  • PDF

A Six-port Bio Radar System for Non-Contact Measurement of Heart and Respiration (호흡 및 심박수 측정을 위한 비 접촉방식의 6-포트 바이오레이더 시스템)

  • Na, Won;Lee, Moon-Que
    • Proceedings of the KIEE Conference
    • /
    • 2008.07a
    • /
    • pp.1393-1394
    • /
    • 2008
  • 본 논문은 사람의 호흡과 심박 수를 0.5 m 의 거리에서 원격 측정하는 레이더 시스템 설계에 관한 내용을 기술한다. 기존에 많이 사용되었던 능동 주파수 혼합기 회로를 파형 간섭 효과를 이용한 6 -포트 회로로 대치하여 설계하였으며 특히 전력 검출기 성능에 따라 낮은 국부 발진기 전력을 사용할 수 있다는 장점을 가짐을 보였다. 본 논문에서는 수신신호 감지를 위한 최적의 국부 발진기의 전력을 제시하였다.

  • PDF

Design of a six-port-manifold mass flow controller system: Establishment of high- precision sampling of airborne pollutants (대기 중 오염물질의 초정밀 채취: 6구 매니폴드 매스-플로우-컨트롤러를 조합한 초고정밀 유량채취 방식의 검정)

  • 김기현;김민영;최여진;최규훈;오상인
    • Proceedings of the Korea Air Pollution Research Association Conference
    • /
    • 2002.11a
    • /
    • pp.65-67
    • /
    • 2002
  • 대기 중 오염물질의 측정은 크게 채취와 분석의 단계로 구분할 수 있다. 오염물질의 측정과 관련된 정도관리도 당연히 이들 2개의 분야에 대한 각각의 가치를 동일하게 비교하여야 한다. 그러나 아직까지 많은 연구주체들에 의해 시도된 대기관측과 관련된 연구분석의 결과들은 분석의 정도관리에 대해 많은 가치를 부여함에도 불구하고, 채취의 정도관리에 대해서는 나름대로 충분한 검정이 이루어지지 않은 경우를 빈번하게 목격할 수 있다 (Kim and Lindberg, 1994). (중략)

  • PDF

Digital Literacy Skills and Utilization of Online Platforms for Teaching by LIS Educators in Universities in Rivers State, Nigeria

  • David-West, Boma Torukwein
    • International Journal of Knowledge Content Development & Technology
    • /
    • v.12 no.4
    • /
    • pp.105-117
    • /
    • 2022
  • The study investigated digital literacy skills and utilization of online platforms for teaching by LIS educators in universities in Rivers State, Nigeria. The study was undertaken as a descriptive survey design. Three research questions and three hypotheses guided this study. The population of the study was twenty-six Lecturers from the three universities in Rivers State where library and information science are offered. The twenty-six constitute the sample size. Census sampling technique was adopted for the study. The instrument titled Digital Literacy Skills and Utilization of Online Platform for Teaching Questionnaire (DLSOPUQ) was used to elicit information from the respondents. Twenty-six copies of the questionnaire were administered and retrieved. Mean (${\bar{x}}$) was used to analyze the research questions and the null hypotheses was tested with t-test at 0.05 level of significance. The study revealed that there is no significant difference between digital literacy and utilization of online platforms for teaching by LIS educators in universities in Rivers State. Further findings revealed that LIS educators do not have the necessary skills to navigate the online environment for teaching without assistance. In conclusion LIS educators should be innovative and update their skills to meet up with global practice. It was recommended among others that LIS educators should be trained and retrained by the university management to cope with online teaching and provision of the right infrastructure by governments for effectives teaching and learning process.