Resul Kara

Binary apple tree: A game approach to tree traversal algorithms

The computer science students mostly face with the difficulties in learning the topics of algorithms courses. Only listening the topic from the teacher or just writing makes the learning volatile. Instead of listening or writing, if there is something visual, it would be more permanent to learn because visuality increases the learning potential and the time for learning is minimized. The adversities of classical education techniques were intended to be eliminated in this study via computer games which are becoming more and more popular in this age. An educational convenience is provided for the subject of tree traversal algorithms. Tree traversal algorithms are one of the basic and confused concepts in algorithms and programming courses in computer science. A game called “binary apple tree” was established to teach and learn the subject easier.

Leakage detection and localization on water transportation pipelines: a multi-label classification approach

One of the main problems of water transportation pipelines is leak which can cause water resources loss, possible human injuries, and damages to the environment. There are many studies in the literature focusing on detection and localization of leaks in the water pipeline systems. In this study, we have designed a wireless sensor network-based real-time monitoring system to detect and locate the leaks on multiple positions on water pipelines by using pressure data. At first, the pressure data are collected from wireless pressure sensor nodes. After that, unlike from the previous works in the literature, both the detection and localization of leakages are carried out by using multi-label learning methods. We have used three multi-label classification methods which are RAkELd, BRkNN, and BR with SVM. After the evaluation and comparison of the methods with each other, we observe that the RAkELd method performs best on almost all measures with the accuracy ratio of 98%. As a result, multi-label classification methods can be used on the detection and localization of the leaks in the pipeline systems successfully.

Comparison of image compression algorithms used in Wireless Multimedia Sensor Networks

Wireless Multimedia Sensor Networks (WMSN) are used to transfer large amount of data like audio, image, and video. The multimedia data which is gathered from the environment is processed and then transferred to another sensor or a sink in WMSN. Except for the special applications, in WMSN, there is only compression operation on the data. In this study, image compression and decompression times of three image compression algorithms: Discrete Cosine Transform -DCT, Set Partitioning in Hierarchical Trees - SPIHT, Low Energy Image Compression Algorithm - LEICA, which are also frequently used for WMSN are compared. The algorithms are first encoded by C programming language and run on a virtual machine with Windows OS, which owns hardware requirements of the sensors. Then, the obtained data is evaluated in terms of compression and decompression times.

TwitterSentiDetector: a domain-independent Twitter sentiment analyser

ABSTRACT Sentiment analysis has become more crucial after the rise of social media, especially the Twitter since it provides structured and publicly available data. TwitterSentiDetector is a domain-dependent and unsupervised Twitter sentiment analyser that focuses on the differences occurred by the informal language used in Twitter. TwitterSentiDetector uses natural language processing techniques alongside the proposed linguistic methods to classify sentiments of tweets into positive, negative, and neutral through the polarity scores obtained from sentiment lexicons. According to tests on widely used Twitter data-sets that contain manually detected sentiments labels alongside tweets, TwitterSentiDetector’s sentiment detection ratio is calculated as up to 69%. When the target sentiment classes are decreased to positive and negative, the detection ratio is increased up to 87%. The results are calculated very similarly when the same data-set is evaluated by the proposed tweet-level context aware sentiment analysis module which confirms the validity of each approach.

A Survey of Spam Detection Methods on Twitter

Twitter is one of the most popular social media platforms that has 313 million monthly active users which post 500 million tweets per day. This popularity attracts the attention of spammers who use Twitter for their malicious aims such as phishing legitimate users or spreading malicious software and advertises through URLs shared within tweets, aggressively follow/unfollow legitimate users and hijack trending topics to attract their attention, propagating pornography. In August of 2014, Twitter revealed that 8.5% of its monthly active users which equals approximately 23 million users have automatically contacted their servers for regular updates. Thus, detecting and filtering spammers from legitimate users are mandatory in order to provide a spam-free environment in Twitter. In this paper, features of Twitter spam detection presented with discussing their effectiveness. Also, Twitter spam detection methods are categorized and discussed with their pros and cons. The outdated features of Twitter which are commonly used by Twitter spam detection approaches are highlighted. Some new features of Twitter which, to the best of our knowledge, have not been mentioned by any other works are also presented.

Image compression techniques in Wireless Multimedia Sensor Networks

Wireless Multimedia Sensor Networks (WMSNs) provide realization of applications which is usable everywhere and address to many fields like mobile health care, environmental surveillance and traffic monitoring. Amount of data causes to traffic in memory resources, difficulties in operation, and excessive power consumption - which is the most important one- for every node while WMSNs transfer multimedia data during those applications. That kind of problems is vital for WMSNs which already have limited resources. Image compression can be one of the effective solutions to overcome those problems. Thus, network lifetime of WMSNs can be increased significantly and the bandwidth can be used in a more effective manner. The main purpose of this study is to investigate image compression algorithms used for WMSNs in the literature in terms of their advantages and disadvantages after giving brief information about WMSNs.

Comparison of real time image transfer in wireless multimedia sensor networks

Wireless Multimedia Sensor Networks (WMSN) allows developing many applications which addresses to many areas like mobile healthcare, environmental monitoring and traffic monitoring. During those applications, real time data transmission is very important in terms system security and usability while the multimedia data is processed and transferred. Namely, it is required to transfer data taken from a sensor to another sensor or to a base station as soon as possible. The most time-consuming part is caused by image compression algorithms. In this study, the computation speeds of the basic image compression algorithms Discrete Cosine Transform (DCT) and Embedded Zero-tree Wavelet (EZW) are compared. This operation is realized on the sensors and the transmission time is not added to the computation time. The algorithms are compared via MATLAB. This study may set light to the efficiencies of some algorithms which are derived from the compared algorithms in real time image transmission.

Analysis of Fuzzy Logic Usage in PBHRA Routing Algorithm in Wireless Ad Hoc Networks

Mobile ad hoc networks are composed of nodes communicating with each other without any infrastructure. Position based routing algorithms used in these networks makes the decision of routing by considering the location information of wireless nodes. In this study, the effect of using fuzzy logic during the decision making about routing of nodes that are using one of the location information based algorithm PBHRA (Position Based Hybrid Routing Algorithm) in the literature has been examined. 50-noded and 100-noded networks that are using PBHRA have been subjected to routing operation with and without using fuzzy logic. The results have been given relatively. It is shown that the usage of fuzzy logic provides the effective usage of band width and battery life, which are counted as the constraints of ad hoc networks.