Journal of Naval Sciences and Engineering

217 - 239

Authors: Osman KABASAKAL, Alev MUTLU

In this study, we focus on the effect of word positions in unsupervised, graph-based keyword extraction. To this aim, we discuss the performance of four node-weighting procedures, namely Word Position (WP), Word Position Bidirectional (WPB), Sentence Position (SP), and Sentence Position Bidirectional (SPB). WP assigns higher weights to words that appear at the beginning of a text. WPB assigns higher weights to words that appear either at the beginning or end of a text. SP assigns higher weights to words that appear in the very first sentences of a text. SPB assigns higher weights to words that appear in sentences that are either close to the beginning or end of a text. Experiments conducted on six benchmark datasets show that WP and SP do not statistically differ. However, for datasets whose keywords appear early in the text WP performs better than SP with no statistical difference, while for datasets where keywords are evenly distributed in text SP statistically performs better than WP.

265 - 282

Authors: Özlem SEVİNÇ KAYA

In this study, the resonance production of the sextet scalar diquarks are studied for the FCC (Future Circular Collider) proton-proton collider with 100 TeV centre-of-mass planned to build at the European Organization for Nuclear Research, CERN. For the scalar diquarks, decay width and cross sections are calculated as a function of the diquark’s mass. Also, to separate the diquark’s signal from the background, the kinematic cuts are applied on diquarks mass and statistical significance calculations are obtained. As a result, at the FCC-pp, for the scalar diquark’s mass, discovery (5), observation (3) and exclusion (2) limit values are given. These mass limit values are compared with mass limit values of the Large Hadron Collider (LHC) with 7 TeV centre-of-mass energy and the High Luminosity-Large Hadron Collider (HL-HLC) with 14 TeV centre-of-mass energy.

309 - 341

Authors: Muhammet Ali YILMAZER, Burak YILDIZ

The second generation intact stability criteria (SGISC) have been developed by the International Maritime Organization’s (IMO) Subcommittee on Ship Design and Construction (SDC). The SGISC involve improving the current intact stability criteria by including dynamic movements of ships in waves. The criteria are structured around five failure modes, pure loss of stability being one of these. This paper presents sample calculations regarding the assessment of pure loss of stability for a Turkish navy tanker. The calculations involve two steps that this study explains: Level 1 and Level 2. In addition, Option A and Option B are used as solution methods for both levels. Minimum metacentric heights (GMmin) are calculated at the lowest draft (Option A) and at different wave crest locations alongside the ship (Option B) for Level 1. Values for the angle of vanishing stability, angle of loll, angle of stable equilibrium and maximum righting lever have been calculated from the GZ curves for Level 2. As a result, the subject ship was found not to be vulnerable to pure loss of stability. Level 1 results for both options are inconsistent due to Level 2 results being consistent.

377 - 393

Authors: Mehmet Burak KOÇAK, Barış BARLAS

Occupants in high-speed patrol boats are subject to impact forces due to various boat motions. These impact forces should be precisely calculated and accounted for when designing seats for occupants. Hull design and cruising speed are the most critical parameters that cause shock and impact on the boat during the journey. In addition, seat design and material also have a major effect on the impact level sensed by the occupant. In this study, Altair software (Hypermesh and Radioss) is used to build a sample Computer Aided Engineering (CAE) seat and occupant model for patrol boats. The occupant CAE model (50th percentile, Hybrid III) used in our study is already available in the software library and has been verified based on physical testing. During investigation, accelerations coming from reference studies are applied on the model and CAE results are investigated to understand occupant kinematics better. Different accelerations, seat foam thicknesses, and seat foam materials are tested numerically in CAE models. Based on the CAE results, strong relation between boat accelerations and impact level on occupant body regions are compared and verified. Acceleration levels and dummy kinematics was investigated with updates in seat foam design and materials. This study has been conducted in order to avoid injuries for patrol boat occupants and to shed a light on the importance of seat design.

413 - 428

Authors: Fatih ERDEN, Ayşe YAVUZ ERKAN, Ahmet Arda ÇOŞAN, Serkan AKSOY

The purpose of this study is analytical studying Initial-Boundary-Value Problem for the novel format of Maxwell’s equations in SI units. A modified version of the Evolutionary Approach to Electromagnetics (EAE) used herein. The problem is considered for the causal electromagnetic oscillations excited by a given external rectangular pulse signal, J(r,t) , in a hollow cavity with lossy metallic walls. The cavity volume V is finite and closed by a singly connected surface S with none of its inner angles exceeds π. Physically, cavity walls are lossy (completely or partially). Graphical results are exhibited demonstrating that the electromagnetic oscillations inside the cavity with metallic surface satisfy the causality principle.