Journal of Naval Sciences and Engineering

27-42

Authors: Deniz KUMLU, Batuhan GÜNDOĞDU

The clutter problem in ground penetrating radar (GPR) images highly effects the performance of target detection ratio. Various methods have been proposed for clutter suppression purposes in the GPR literature. They can be mainly grouped as low rank, low rank and sparse and tensor-based decomposition methods. Principal component analysis (PCA) and robust principal component analysis (RPCA) are classicle approaches and could be classified as low rank and low rank/sparse decomposition methods, respectively. Recently proposed tensor-based methods provide an alternative perspective of solving the low rank and sparse decomposition to handle challenging situations such as shallowly buried objects or rough surface situations. Motivated by the performance of Tensor-based methods, we propose a new pre-transformation step for tensor robust principal component analysis (TRPCA) and compare it with the PCA and RPCA methods over a simulated GPR dataset. Our proposed method outperforms the classical PCA and recent RPCA methods both visually and quantitatively in terms of clutter removal.

77-102

Authors: Muhammet DEVECİ, Nezir AYDİN, Ali Osman KUSAKCI

The number of passengers in public transport has decreased significantly in major cities around the world due to COVID-19. As residents of many countries work from home, they have avoided public transport to minimize their exposure to the outbreak and have changed their way of traveling within their cities due to major changes in local public transport services. Istanbul is one of the cities most affected by the pandemic in terms of the daily number of passengers using public transportation. For the first time since the pandemic started in Istanbul, the use of urban public transportation has decreased by more than 90 percent. The aim of this study is to examine the measures taken in Istanbul public transport in order to prevent the spread of the coronavirus pandemic. In addition, the trends in public transport and inter-modes demands during COVID-19 are analyzed. The results showed that COVID-19 measures to protect the health of passengers in Istanbul public transport are in line with global practices during the initial stage of the pandemic.

131-163

Authors: Emrah KÖKSALMIŞ, Serhat AYDIN

With the impact of the COVID-19 pandemic continuing to be felt globally, it is essential that people quickly adapt to a new virtual business landscape, in order to continue to provide a valuable conference experience. E-conference, in other words web conference or virtual conference, is an online conference that involves people participating in a conference through a virtual environment on the web, rather than meeting in a physical location. The objective of this paper is to inspect several reasons of behavioural intention to use an e-conference system by utilizing the modified technology acceptance model (TAM). Together with primary elements of TAM, in this particular paper, additional constructs such as satisfaction, time, price savings, technical support, mobile anxiety, social influence and convenience are taken into account. Total of 203 questionnaires is gathered through academicians in Turkey. To evaluate the data and examine the proposed hypotheses, the Structural Equation Modeling (SEM) methodology is implemented by utilizing SmartPLS 3.2.7. The results indicate that convenience, mobile anxiety, satisfaction, perceived usefulness and social influence are significantly predicting the behavioural intention. This paper enables theoretical and practical implications for authorities seeking to implement an e-conference.

181-203

Authors: Murat Kağan KOZANHAN

Piracy is an illegal act that has existed since the beginning of the sea trade. However, efforts continue to be made to or to commit terrorist acts in the seas through piracy activities today. Piracy and terrorist acts at sea threaten/affect not only commercial security but also international maritime security and therefore international security. On October 7, 1985, the hijacking of the Achille Lauro ship brought up the necessity of making an international agreement and cooperation of states to prevent illegal acts at sea, and the Convention for the Suppression of Unlawful Acts against the Safety of Maritime Navigation (1988 SUA Convention) and its Additional Protocol were signed. The terrorist acts of September 11, 2001, besides the acts of piracy, also led to the questioning of terrorism and international maritime security in this context and the actions that can be done at sea on 14 October 2005 were rearranged. Within this context, the development of the 1988 SUA Convention was examined in this study, and then the intervention made by the Russian Federation based on the SUA Convention and its Additional Protocol to the Arctic Sunrise ship, which operates on behalf of the Greenpeace Organization, and evaluations were made within the framework of the decisions made as a result of the case being brought to the judiciary.