Efficiently detecting the nearest navigational dangers in Electronic Chart Display and Information Systems (ECDIS) remains pivotal for maritime safety. However, the software implementation of ADMAR(Automatic Distance measurement and Ranging) functionality faced challenges, necessitating extensive computations across ENC cells and impacting real-time performance. To address this, we present a novel method employing dynamic programming. Our proposed algorithm strategically organizes nodes into a tree structure, optimizing the search process towards nodes likely to contain navigational hazards. Implementation of this method resulted in a notable sevenfold reduction in computation time compared to the conventional Brute Force approach. Our study established a direct correlation between the ADMAR functionality and node count, achieving error margins deemed acceptable for practical navigation scenarios. Despite this theoretical progress, minor errors in results prompt further refinement. Consequently, future iterations will explore varying values for N, considering hierarchy and cell sizes to enhance algorithmic precision. This research signifies a potential advancement in optimizing navigational danger detection within ECDIS, offering a promising avenue for improved efficiency. By introducing a dynamic programming-based approach, we have streamlined the detection process while acknowledging the scope for algorithmic refinement in subsequent studies. Our findings underline the feasibility of employing dynamic programming to enhance navigational danger detection, emphasizing its potential in ensuring maritime safety. This work lays a foundation for future research endeavors, aiming to fine-tune algorithms and advance navigational safety measures in ECDIS.

최근 국내 일부 항해사들은 해운산업의 어려운 취업환경을 극복하고, 직업선택의 저변을 확대하기 위하여 승선경력을 기반으로 국내외 교육기관에서 DP운항사 교육을 이수하여 직종을 전환하고자 노력하고 있다. 그러나 아직까지 국내에서는 해양플랜트 서비스 산업 이 활성화 되어있지 않기 때문에 동 분야로 진출하고자 하는 항해사들은 어렵게 자격취득을 위한 실습을 마치고 대부분 해외선사로 진출 하고 있다. 그럼에도 불구하고 DP운항사로 취업을 희망하는 항해사들은 경력을 중시하는 해외 해양플랜트 기업의 보수적인 채용 절차, 비 영어권 출신자의 언어사용의 한계, 다문화 승선생활의 어려움, 필수 직무요건에 대한 체계적인 정보 부족 등의 이유로 구직 단계에서 부터 어려움을 겪고 있다. 따라서 이 연구는 DP운항사가 갖추어야 할 직무능력 및 자격 요건을 분석하여 국가에서 요구하는 최소한의 능력 수 준을 제시하고 있는 NCS 표준 개발을 위한 기초자료를 제공하고, DP운항사 전문인력양성을 활성화하기 위한 방안을 제시하는 데 목적을 두고 있다. 본 연구의 결과로서, DP운항사의 직무 분류, 직무능력표준 및 경력개발경로를 제시하였고, DP운항사 양성 활성화 방안으로서 DP 실습선박의 공동 활용, DP 전문 교원 양성 및 정부주도 NCS 수출모델을 제안하였다.

본 연구에서는 10년간(2001 2010) IMCA에 보고된 DP 선박 LOP(Loss of Position)사고 612건에서 인적오류에 의한 사고 103건을 확인하여 이를 HFACS로 분류하였다. 그리고 이를 베이지안 네트워크에 적용하여 인적오류의 조건부 확률을 확인해 보았다. 그 결과 103건의 인적오류관련 사고는 모두 불안전한 행동에 의해서 발생하였고 이들 중 기술 기반 오류가 70건(68.00 %)으로 가장 큰 인적오류 비율을 차지하였다. 기술 기반 오류 중에서는 부주의한 DP 선박 운용 60건(58.3%), 절차 미 준수 8건(7.8%)이었고, 의사결정 오류에 의한 잘못된 조종이 21건(20.8%)을 차지하였다. 이러한 HFACS 분류의 베이지안 네트워크 적용을 통해서는 불안전한 감독(68%)이 불안전한 행동의 가장 큰 잠재적 요인으로 작용하고 있다는 것을 확인 할 수 있었다. 결론적으로 HFACS와 연계한 베이지안 네트워크는 인적오류를 분석하는 데 유용한 도구임을 확인 할 수 있었고, 분석 결과를 바탕으로 DP 선박안전 운용을 위한 정책, 내부 관계, 훈련등과 같은 인적오류를 경감 및 제거하기 위한 권고 9가지를 제안하였다.

This study analyzes the resistance spot weldability of DP60 steels. To analyze the resistance spot weldability of DP60 steels, tensile strength test and macro-section test were conducted for the resistance spot welds. Acceptable welding conditions were determined as a function of the resistance spot welding process parameters such as electrode force, welding time, and welding current. The lower limit of the welding lobe was the minimum shear tension strength for 590MPa-grade steel while the upper limit was determined whether or not expulsion was detected.

This study describes a hydrogen embrittlement evaluation of the subsurface zone in 590DP steel by micro-Vickers hardness measurement. The 590DP steel was designed to use in high-strength thin steel sheets as automotive materials. The test specimens were fabricated to 5 series varying the chemical composition through the process of casting and rolling. Electrochemical hydrogen charging was conducted on each specimen with varying current densities and charging times. The relationship between the embrittlement and hydrogen charging conditions was established by investigating the metallography. The micro-Vickers hardness was measured to evaluate the hydrogen embrittlement of the subsurface zone in addition to the microscopic investigation. The micro-Vickers hardness increased with the charging time at the surface. However, the changing ratio and maximum variation of hardness with depth were nearly the same value for each test specimen under the current density of 150 mA/cm2 and charging time of 50 hours. Consequently, it appears that hydrogen embrittlement in 590DP steel can be evaluated by micro-Vickers hardness measurement.

High strength sheet steels for automobile are seriously compromised by hydrogen embrittlement. This issue has been continuously studied, but the field of interest, which lies between microstructural characteristics and hydrogen behavior with hydrogen charging, has not yet been thoroughly investigated. This study was done to investigate the behavior of hydrogen according to the hydrogen volume fraction on 590MPa grade DP steels, which are developed under hydrogen charging conditions as high strength sheet steels for automobiles. The penetration depths and the mechanical properties, according to charging conditions, were investigated through the distribution of micro-hardness and the microstructural observation of the subsurface zone. It was found that the amount of hydrogen trapping in 590MPa DP steels was related to the austenite volume fraction. It was confirmed that the distribution of micro-hardnesses according to the depth of the subsurface zone under the free surface showed the relationship of the depth of the hydrogen saturation between the charging conditions.

목적 : 본 연구는 한국형 발달프로파일-Ⅲ(K-DP-Ⅲ) 국내의 실정에 맞게 표준화하기 위한 예비연구로, 전문가들의 논의를 거쳐 한글로 문항을 번역하고 한국 실정에 맞게 수정하여 K-DP-Ⅲ를 개발하고, 이에 대한 신뢰도와 타당도를 제시하고자 시행되었다. 연구 방법 : 아동전문가들의 번역과 관련 전문가들의 고증을 거쳐 한국형 발달프로파일-Ⅲ를 개발하였으며, 2009년 11월 5일부터 동년 11월 10일까지 두 개 도시(서울, 원주)에서 3세부터 5세까지 정상발달을 보이는 아동 49명을 대상으로 신뢰도와 타당도 검증을 실시하였다. 한국형 발달프로파일-Ⅲ의 타당도 비교에는 한국판 덴버발달선별검사Ⅱ(K-DDST-Ⅱ)와 한국판 적응행동척도(K-ABS)를 사용하였다. 결과 : 평가결과 한국형 발달프로파일-Ⅲ의 신뢰도는 .86􀅭.90로 조사되었으며, K-DDST-Ⅱ와 K-ABS와의 항목별 상관관계에서도 높은 수준의 상관관계를 보여 타당도가 높은 평가도구임을 확인하였다. 결론 : 본 예비 연구를 통하여 한국형 발달프로파일-Ⅲ는 아동의 발달을 평가하는데 있어 신뢰할만하고 타당한 평가도구임을 검증 하였다.

The microstructures and mechanical properties of Dual Phase (DP), Transformation-Induced Plasticity (TRIP), and Quenching & Partitioning (Q&P) steels were investigated in order to define the strengthening mechanism of 0.2 C steel. An intercritical annealing between Ac1 and Ac3 was conducted to produce DP and TRIP steel, followed by quenching the DP and TRIP steel being quenched at to room temperature and by the TRIP steel being austemperingaustempered-air cooling cooled the steel toat room temperature, respectively. The Q&P steel was produced from full austenization, followed by quenching to the temperature between Ms and Mf, and then enriching the carbon to stabilize the austenite throughout the heat treatment. For the DP and TRIP steels, as the intercritical annealing temperature increased, the tensile strength increased and the elongation decreased. The strength variation was due to the amount of hard phases, i.e., martensite and bainite, respectively in the DP and TRIP steels. It was also found that the elongation also decreased with the amount of soft ferrite in the DP and TRIP steels and with the amount of the that was retained in the austenite phasein the TRIP steel, respectively for the DP and TRIP steels. For the Q&P steel, as the partitioning time increased, the elongation and the tensile strength increased slightly. This was due to the stabilized austenite that was enriched with carbon, even when the amount of retained austenite decreased as the partitioning time increased from 30 seconds to 100 seconds.

This paper provides a unified analysis for the three types of right displacement in English as the clause-final right-displaced element has in common the function of specifying/elaborating on what has been left referentially indeterminate or blank in the preceding clause. We take the surface make-up of the three constructions at issue to indicate that the right-displaced element has coordinate structure relation with the preceding 'propositional' constituent such as vP or TP. Based on this initial conception of the three constructions at issue, we make three points. First, we argue that these constructions involve clausal coordination and their surface forms are derived by eliding the second conjunct except for the base-generated/ leftward-moved element outside it. Second, we show that the economy of structure-building is at work in the formation of the two coordinate conjuncts in the constructions, accounting for the well-known Right Roof constraint or clause-boundedness condition. Third, we also demonstrate that the ban on P-stranding heavy NP shift of a certain argument element follows from the unavailability of an implicit argument to the relevant position of the first conjunct.

Dynamic Positioning System(DPS)은 그 신뢰성 및 redundancy(대체) 시스템에 따라 IMO 및 각 선급에서 3개의 class(등급)로 나 누고 있다. IMO MSC/Circ 645에 의하면 DPS는 Class 1, 2, 및 3로 나누고 있으며 등급이 높을수록 좀 더 신뢰성 있고 안전하게 DP 선박을 운용할 수 있다. 국내에서 많은 DP Class 선박들이 건조되고 있는 상황에서 DP Class 1선박의 개조를 통해서 DP Class 2로 변경하거나 DP Class 2선박을 신조 또는 중고선으로 구입하는 경우 무엇을 검토하고 확인해야 하는지에 대한 구체적인 실무 자료가 부족하고, DP Class 1 선박을 Class 2로 변경하여 다시 매도하는 새로운 산업분야의 개척에 있어 국내 사례를 바탕으로 한 연구가 필요할 것으로 판단된다. 이에 본 연구에서는 DP Class 1선박을 DP Class 2 선박으로 변경하기 위해서는 어떠한 IMO 및 선급의 DP class 요건의 충족이 필요하며 이를 위해 서 어떠한 설비의 변경 및 추가가 필요한지를 국내에서 있었던 실제 사례를 통해서 연구해 보았다. DP 선박 Class 변경을 위해서는 FMEA를 통해서 파악되는 DP 선박의 동력 시스템, thruster 시스템 및 제어 시스템 3가지의 주요 시스템에 대체(redundancy)기능을 갖추어야 한다. 동 력 시스템은 단일의 발전기, 배전반등에 문제가 발생해도 DP 기능을 유지할 수 있어야 하며, 더불어 PMS기능을 갖추고 있어야 한다. thruster 시스템은 단일의 고장이 발생하더라도 선박의 Surge, Sway 및 Yaw를 남은 thruster 시스템으로 자동 제어 할 수 있어야 한다. 각종 제어 시스템, PRS 및 센서는 여러개를 설치하여 단일의 장비고장에도 DP 기능을 유지 할 수 있어야 한다.

This paper examines the identity of null objects in Korean. For the last two decades, null objects in this language have been argued to derive from either base-generation as an empty pronoun or ellipsis/deletion. To resolve this controversial issue, we scrutinize some previous arguments supporting one analysis or the other for null objects. We set forth a background for the discussion of them, starting with the diagnostic that Chung et al. (2011) uses to distinguish VP and TP ellipsis in English. We then turn to Hoji's (1998) and Ahn and Cho's (2011) test utilizing the availability of a sloppy-like reading, and then to Hoji's (2003) and Bae and Kim's (2012) probe employing R-expressions. Showing that all these diagnostics are not effective as much as they have been claimed to be, we use the new test capitalizing on the extraction out of an ellipsis site, arguing that null objects in Korean derive from deletion/ellipsis rather than base-generation as pro.

Centralized safety stock in a periodic replenishment system which consists of one central warehouse and m regional warehouse can reduce backorders allocating the centralized safety stocks to regional warehouse in a certain instant of each replenishment cycle. If the central warehouse can not monitoring inventories in the regional warehouse, then we have to predetermine the instant of allocation according to demand distribution and this instant must be same for all different replenishment cycle. However, transition of inventory level in each cycle need not to be same, and therefore different instant of the allocation may results reduced shortage compare to the predetermined instant of allocation. In this research, we construct a dynamic model based on the assumption of monitoring inventories in the regional warehouse everyday, and develop an algorithm minimize shortage in each replenishment cycle using dynamic programming approach.