• Journal of Navigation and Port Research
• /
• v.39 no.3
• /
• pp.165-172
• /
• 2015

The class of Dynamic Positioning System is divided in 3 classes depending on its redundancy and reliability according to IMO and classification society. There are 3 DP classes such as DP Class 1, 2 and 3 according to IMO MSC/Circ. 645. Higher DP class vessel has higher reliability, since redundancy concept is applied to the DP vessel depending on its DP class and can operate more safely. There are not enough information about DP class notation, which are needed when a company builds a new or buys second hand DP vessel or modifies DP classes, even the Korean shipyard is building a lot of DP vessels now. Also, the practical case of DP vessel modification, which had been done in Korea, to meet DP notation of IMO and classification society, will be helpful for DP vessel modification and sales industry development in Korea as a new business. As such this research identified what kind of requirements need to be taken into account to be from DP class 1 to DP class 2. The real DP class modification case is used to identify the requirements of DP class upgrade. Through the FMEA the redundancy concept on power system, thruster system and DP control system need to apply for DP class upgrade. The power system have to keep its DP function even if just a single fault happens on the generator or switchboard. Also, the PMS is required to monitor and control power system. Ship's Surge, Sway and Yaw movements can be controlled by the remaining thruster system after a single thruster fails. Lastly, multiple installation of PRS, sensors and DP control system are required to keep DP ability after a single fault on the DP control systems.

• Textile Coloration and Finishing
• /
• v.10 no.5
• /
• pp.24-31
• /
• 1998

The effects of DMDHEU alone and DMDHEU/Fluorochemical(FC) combined treatment on the physical properties of 75％/25％ cotton/polyester(CP) blended fabrics were investigated. FC water repellent and DMDHEU durable press finishes were applied in combination to CP fabrics to provide good water repellency as well as great durable press(DP) performance. The physical properties of the fabrics were evaluated by wrinkle recovery angle(WRA), DP performance, contact angle, demand wettability, and water repellency. The durable press/water repellent finished(DP/WR) CP fabrics show considerably improved WRA and DP performance. The DP/WR finishes do not change the water contact angie of polyester fibers significantly, while the DP finishes increase it. Both DP and DP/WR finishes increase the contact angle of cotton fibers. The water uptake amount increases in the following order : DP/WR cotton, DP/WR CP＜DP cotton, DP CP ＜ Control CP, Control cotton. The water uptake amount increases in the following order DP/WR CP, DP/WR cotton ＜DP cotton ＜DP CP＜Control CP, Control cotton. Considerable improvements for water repellency are imparted to the CP fabrics treated with DP/WR, and the level of improvement is not significantly different from that of the DP/WR cotton fabrics. These results lead to the conclusion that DP/YVR treatments a single pad bath on CP are effective finishes for improving both DP performance and water repellency.

• Journal of Navigation and Port Research
• /
• v.39 no.3
• /
• pp.149-156
• /
• 2015

The Dynamic Positioning System consists of 7 elements which are namely Power system, Human machine interface, DP Computer, Position Reference System(PRS), Sensors, Thruster system and DP Operator. Incidents like loss of position(LOP) on DP vessel usually occur due to errors in these 7 elements. The purpose of this study is to find out safety operation method of DP vessel through qualitative and quantitative analyze of DP LOP incidents which are submitted to IMCA every year. The 612 DP LOP incidents submitted from 2001 to 2010 were analyzed to find out the main cause of the incidents and its rate among other causes. Consequently, the highest rate of incidents involving DP elements are PRS errors. DP computer, Power system, Human error and thruster system came next. The PRS has been analyzed and a flowchart was drawn through expert brainstorming. Also, the conditional probability has been analyzed through Bayesian Networks based on this flowchart. Consequentially, the main causes of drive off incidents were DGPS, microwave radar and HPR. Also, this study identified the main causes of DGPS errors through Bayesian Networks. These causes are signal blocked, electric components failure, relative mode error, signal weak or fail.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.23 no.6
• /
• pp.628-638
• /
• 2017

In response to difficult employment conditions in the maritime industry and a desire to expand their career options, domestic mates are persuing DP operator training at institutions both domestically and abroad based on their shipboard experience. However, since the offshore plant service industry has not yet been established in Korea, those seeking to enter this field have difficulty acquiring qualifications and most seek work overseas for offshore shipping companies. Individuals wishing to work as DP operators are likely to face more conservative recruitment processes with overseas offshore shipping companies, focusing on career language restrictions as they will be non-native speakers relative to the foreign company, difficulty living in a multi-cultural environment, and lack of systematic information on essential job requirements. For these reasons, domestic mates have difficulty seeking jobs. Therefore, this study analyzes the capabilities and qualification required to be a DP operator to provide basic data for developing NCS standards representing a minimum level of competency. These standards can be applied by the government to develop plans for professional training for DP operators. In study, job classifications, competency standards and career development paths for DP operators have been proposed along with joint use of DP training vessels, to train specialized DP instructors. An NCS export model led by the government to activate professional training for DP operators is also presented.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2014.10a
• /
• pp.28-30
• /
• 2014

Dynamic Positioning System(DPS)은 그 신뢰성 및 대체 시스템에 따라 IMO 및 각 선급에서 3개의 class(등급)로 나누고 있다. IMO MSC/Circ 645에 의하면 DPS는 Class 1, 2, 및 3로 나뉘어 있으며 등급이 높을수록 좀 더 신뢰성 있고 안전하게 DP 선박을 운용할 수 있다. 이러한 DPS의 등급은 DP 선박을 건조할 때 그 선박의 사용 목적 및 필요성 신뢰도에 따라 건조되고 있으나 최근에는 이미 건조되어 있는 DP 선박의 등급을 개조를 통해 변경하여 사용하기도 한다. 본 연구에서는 DP Class 1선박을 DP Class 2 선박으로 변경하기 위해서는 어떠한 IMO 및 선급 요건의 만족이 필요하며 이를 위해서 어떠한 설비의 추가가 필요한지를 알아보고 이를 실제 사례를 통해 확인 및 검증해 본다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2015.05a
• /
• pp.28-28
• /
• 2015

본 연구는 KICT X밴드 이중편파 레이더 관측자료를 이용하여, 우리나라 기상조건에서 X밴드 이중편파 레이더 $K_{DP}$ 추정 기법에 따른 강우강도 추정의 차이를 비교 검토하였다. 이중편파 레이더로 $K_{DP}$ 기반의 정확도 높은 강우강도 분포 추정에 있어, $K_{DP}$ 추정의 방법에 따라서 추정된 $K_{DP}$의 공간 분포는 상당한 차이를 보이게 된다. 추정 기법만을 볼 때, 이는 주로 ${\Phi}_{DP}$로부터 기울기를 산정하는 방법과 기울기를 산정하는 윈도우의 크기에서 차이가 발생한다. 윈도우의 크기는 일반적으로 호우의 강도에 따라 달리 적용하는 것이 $R-K_{DP}$ 관계에서 보다 정확도가 높은 것으로 알려져 있다. $K_{DP}$ 산정 기법에 따른 차이 검토를 위해 기울기 산정 기법, 필터(FIR) 상수 및 ${\Phi}_{DP}$ 기울기 산정을 위한 윈도우 크기에 따른 강수 추정의 정확도를 검토하였다.

• Transactions of Materials Processing
• /
• v.29 no.1
• /
• pp.11-19
• /
• 2020

For microstructural analysis of a friction stir welded (FSWed) joint of advanced high-strength steels, dual phase (DP) and complex phase (CP) steels, are studied. FSWed joints are successfully fabricated in the following four cases: (i) DP/DP; (ii) CP/CP; (iii) DP/CP, where the advancing side is DP and the retreating side is CP; (iv) CP/DP, where the advancing side is CP and the retreating side is DP. The stir zone (SZ) of (i) the DP/DP joint mainly consists of lath martensite, while the stir zone of (ii) the CP/CP joint consists not only of lath martensite but also of bainite. In the case of (iii) DP/CP and (iv) CP/DP, they exhibit a similar microstructure including acicular-shaped phases in the joints; however, cross-sections of the joints show differences in material mixing in each case. In (iv) the CP/DP joint, temperature towards the CP steel is sufficient to cause softening, thus leading to better mixing than that in (iii) DP/CP. The phases of the SZ in each of the four cases are formed by phase transformation during the FSWed process; however, the transformed phase volume fraction of CP steel is lower than that of DP steel, indicating that dynamic recrystallization occurs mainly in CP steel. The hardness values of the SZ are significantly higher than those of the base materials, especially, the SZ of (iii) the DP/CP joint has the highest value due to highest fraction of lath martensite.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2012.06a
• /
• pp.401-402
• /
• 2012

해양 자원의 개발이 연안에서 심해로 이동하면서 해양플랜트 건조도 또한 심해라는 특수한 상황에서 운용될 수 있도록 건조되고 있다. 여러 가지 운용 시스템 중 Dynamic Positioning(DP) 시스템은 해상에서 해양 구조물을 일정기간동안 원하는 위치를 유지 시켜주는 시스템으로써 다양한 선박 및 해양플랜트에서 사용되고 있다. 이러한 DP 시스템은 기본적으로 GPS를 이용하여 해상에서 그 위치를 유지하고 있지만 그 외에도 다양한 Position Reference 시스템이 사용되고 있다. 이에 본 논문에서는 DP 시스템의 기본적인 원리와 DP Class 구분 그리고 DP 시스템에 사용되는 다양한 Position Reference 시스템에 대해서 개략적으로 다루고자 한다.

• Journal of the Korean Applied Science and Technology
• /
• v.37 no.4
• /
• pp.778-785
• /
• 2020

The purpose of this study was to investigate in vitro antibacterial activities of pozzolan against super bacteria and intestinal bacteria. There were four treatment groups: 1) CON, pozzolan free control group; 2) DP0.3, microbial culture medium prepared by mixing distilled water and 0.3% of pozzolan powder; 3) DP0.5, microbial culture medium prepared by mixing distilled water and 0.5% of pozzolan powder; and 4) PE, microbial culture medium prepared with pozzolan powder extracts without adding distilled water. The count of Lacctobacillus casei was significantly higher in the DP0.3 group compared to CON (P<0.05). However, it showed no significant difference compared to other treatment groups. Numbers of Clostridium butyricum, Escherichia coli, and Salmonella typhimurium were significantly lower in pozzolanic treatment groups compared to CON (P<0.05). Clostridium butyricum and Salmonella typhimurium counts were significantly different among DP0.3, DP0.5, and PE groups (P<0.05). Counts of E. coli were also significantly between DP0.5 and PE groups (P<0.05). Counts of MRSA and VRE were significantly lower in pozzolanic treatment groups compared to CON (P<0.05). MRSA counts were significantly different among DP0.5, DP0.3 and PE groups. VRE counts were significantly higher in the order of PE > DP0.3> DP0.5> CON (P<0.05). These results suggest that pozzolan could be used as a dietary silicate supplement and a natural antibacterial agent for livestock if its antimicrobial activity against super bacteria and harmful bacteria in the intestine is confirmed.

• The Journal of the Acoustical Society of Korea
• /
• v.13 no.2
• /
• pp.5-12
• /
• 1994

This paper proposes One Stage MSVQ/DP method for word recognition system university administration branch names are selected for the recognition experiment and 10 LPC cepstrum coefficients is used as the feature parameter. Besides the speech recognition experiments by proposed method, for comparision with it, we perform the experiments on the same data by Level Building DTW and One Stage DP method. The Recognition rates with the LBDTW and the One Stage method are $83.3\%$ and $87.5\%$, but the recognition rate with the proposed method is $91.6\%$.