Journal of Naval Sciences and Engineering

7

Authors: Tolga ENSARİ

In this article, we use projected gradient descent nonnegative matrix  factorization (NMF-PGD) method and make pattern recognition analysis  on ORL face data set. Face recognition is one of the critical issues  in our life and some security, daily activities and operations use  this well known application area. NMF-PGD is a type of nonnegative  matrix factorization (NMF) which defined in the literature. In the  study, derived NMF-PGD definition and algorithm has been used in order  to classify the ORL face images. We give the experimental results in a  table and graph. According to experiments, face recognition accuracy  rates have different accuracy values because of the k - lower rank  value. We change k-values between 25 and 144 to see the performance of  NMF-PGD. At the end, we make some analysis and comments on the  recognition rates. Additionally, NMF-PGD can also be used for  different kind of pattern recognition problems.

14

Authors: Hakan DEMİR, Mehmet Bilge Kağan ÖNAÇAN, Ahmet DURMAZ, Mehmet YÜKSEL

The main motivation of this research is to examine effects of “5S applications” which is similar to Kaizen philosophy, on excellence perceptions of firms in food sector. In this context, a questionnaire was applied to the logistics department employees of randomly chosen firms that operate in Istanbul and Kocaeli districts. Data obtained from surveys were subjected to structural equation modeling test. According to the results, overall 5S applications showed positive and significant effects on excellence in business variable, excluding “cleaning”. Moreover, outstanding effect of “sustain” application is an intriguing finding of this research. With the importance that efficiency concept has today, it is evaluated that the results obtained in this study will be beneficial to organizations, especially during their process improvement activities by being the first research in food sector that seeks connection between the 5S and excellence.

8

Authors: Ertan YAKICI

In this case study, we have investigated the optimal design of a network of warehouses to be pre-positioned for humanitarian relief operations to be executed when expected disasters happen. A model which is previously introduced in the literature is applied with the most recent data. The model responds to decision requirements in both locations of warehouses and allocation of resources to these warehouses, assuming the disaster pattern of last decade will continue. A sensitivity analysis is also conducted to observe how the average response time changes as the allowed number of warehouses increases.

13

Authors: Hakan Selim Canca

The use of force is resorted by States as a form of dispute settlement generally as a last resort. But Article 2(3) of the United Nations (UN) Charter states that all members shall settle their international disputes by peaceful means. Article 2(4) bans the unilateral use or threat of force by States. In the customary international law, Article 2(4) is interpreted as a prohibition against the use of force focusing on restricting the use of military instruments. This instrument-based interpretation of the use of force causes the responsibility of States which deploys cyber instruments to cause physical damage in the target States’ critical infrastructures, remain outside the scope of Article 2(4). There are doctrinal difficulties in examining current international law on use of force and self-defense in cyberspace, while the legal frameworks for defining the parameters of operations in cyberspace are not clear. As being unforseen until this age of information and cyber technology, the prohibition of the use of force interpreted from Article 2(4) should be evolved to cover coercive uses of cyber instruments being used to have destructive effects in the enemy’s physical infrastructures such as telecommunications, transportation, power systems, finance and emergency services. Categorizing the cyber attacks as having physical effects to critical infrastructure and not having any physical effects can be the first step to solve the problem of evolving the article to cover cyber attacks within the concept of use of force. Then the efforts may be concentrated on the cyber attacks having physical effects on the enemy’s infrastructures to be considered as a use of force. The main problem is that there would be an unwillingness of the powerful States which are likely to use the opportunities of cyberspace in Inter-State coercion to evolve the interpretation of the article, while the technology-dependent or powerless States would have a volition to evolve the Article.

22

Authors: Ali Saygun SAYGI, Ersoy BEŞER, Murat ÜNLÜ

High frequency switched-mode DC-DC converters are widely used in industry such as battery charging, renewable energy, fuel-cell, power factor correction, LED lighting applications, due to their low response time, easy controlling and high power density. However, at high switching frequency, switching losses, electromagnetic interference (EMI) and lower efficiency become substantial problem. These problems must be eliminated or reduced by using additional passive and active snubber cells in order to operate the converter with soft switching (SS) instead of hard switching (HS). In this paper, properties of soft switching methods named as zero voltage transition (ZVT), zero current transition (ZCT), and zero voltage zero current transition (ZVZCT) developed by combining the ZVT and ZCT, zero voltage switching (ZVS) and zero current switching (ZCS) are studied and discussed, simulations of soft switching DC to DC boost converters including these methods are accomplished for 500W and 1kW power at switching frequency of 100 kHz.