Arama Sonuçları
Listeleniyor 1 - 10 / 42
Yayın Generic BER analysis of VLC channels impaired by 3D user-mobility and imperfect CSI(Institute of Electrical and Electronics Engineers Inc., 2021-07) Reddy Sekhar, K.; Miramirkhani, Farshad; Mitra, Rangeet; Turlapaty, Anish ChandVisible light communications (VLC) has emerged as a high-speed, low-cost, and green supplement for the existing radio frequency (RF) based infrastructures. However, the performance of VLC based systems is found to degrade significantly due to detrimental outages caused by non-negligible variations in the VLC channel-gain, that are jointly induced by radial user-mobility and random photodetector-orientation (together designated as 3D mobility in this letter). In addition to the 3D user-mobility mentioned above, the performance of VLC based systems is further limited by imperfect channel-state information (CSI). Such degradations in the VLC-link caused by the aforementioned factors necessitate the quantification of performance-metrics for further benchmarking/receiver-design. In this work, an analytical expression for bit-error rate (BER) is derived for a single LED indoor VLC system considering the radial user-mobility, random receiver orientation, and imperfect CSI altogether. Further, the derived BER expressions are validated using computer-simulations using typical VLC channel models from the literature. A close agreement between the analytical and the simulated BER is observed, which verifies the accuracy of the presented analysis.Yayın Pros and cons of using building information modeling in the AEC industry(ASCE-AMER Soc Civil Engineers, 2019-08-01) Seyis Kazazoğlu, SenemAlthough a plethora of studies on building information modeling (BIM) have been conducted in the last decade, none of the previous studies collate and/or prioritize the benefits, risks, and challenges of BIM based on the data collected from a comprehensive literature review and subject matter experts (SMEs). In order to allow architecture, engineering, and construction (AEC) professionals and academics see the true potential of BIM in a wider context and help them understand its multiorganizational and multidisciplinary functions, there is an obvious necessity for identifying, classifying, and prioritizing the pros and cons of BIM; however, such a study is still currently absent in the AEC literature. The aim of this study is to identify, classify, and rank the pros and cons of BIM that address the benefits, challenges, and risks of BIM in the transition from computer-aided design (CAD). A literature review was performed and face-to-face semistructured interviews with SMEs on BIM were conducted for identification and classification purposes. A total of 41 types of benefits, 11 types of risks, and 13 types of challenges of BIM were identified via triangulation of literature review and face-to-face semistructured interviews with SMEs. The Delphi method was performed for prioritizing the benefits of BIM in terms of time, cost, and sustainability as well as the risks and challenges of BIM encountered in the transition process from CAD to BIM. The interrater agreement and significance-level statistics were performed to analyze and validate the consensus reached by the Delphi panel experts. This paper contributes to the existing body of knowledge on BIM by providing comprehensive identification and classification of the benefits, challenges, and risks of BIM, and prioritization of the benefits for BIM in terms of time, cost, and sustainability as well as the risks and challenges of BIM. The priority rankings of benefits, risks, and challenges of BIM ensure successful completion of projects and create additional value by allowing professionals to make well-informed decisions that support decreasing time and cost-related waste in the transition process from CAD to BIM.Yayın Yeni çalışma hayatı, gerekleri ve performans değerlendirme kriterleri(Işık Üniversitesi, 2021-01-19) Kılıç, Mina Merve; Teker, Suat; Işık Üniversitesi, Sosyal Bilimler Enstitüsü, Yöneticiler İçin İşletme Yönetimi Yüksek Lisans ProgramıÇağımız bilgi ve teknoloji çağıdır. Bu anlamda işletmeler maliyetlerini düşürmek ve kar marjlarını yükseltmek için yeni çalışma şekillerini benimse sürecindedir. Özellikle günümüzde Covid-19 pandemisi ile birlikte pek çok işletme karma ve uzaktan çalışma şekline geçiş sağlamıştır. Uzaktan ve karma çalışma şeklinin işletmelere birçok faydasının yanı sıra, teknik altyapı eksikliği, işletmelerin bu anlamda yeterlilik durumu, çalışanların sisteme adaptasyon durumu ve çalışanların performans değerlendirilmesi gibi konuların belirsizliği ve yetersizliği sürecin üzerinde düşünülmesi ve önlem alınması gereken konularındandır. Bu çalışmanın amacı uzaktan ve karma çalışma sisteminin gerekleri ve performans değerlendirme kriterlerinin araştırılması ve bu anlamda literatüre katkı sağlanmasıdır. Bu amaçla çalışmada uzaktan çalışma ve performans değerlendirme konularına değinilmiş ve bu konu ile ilgili farklı sektörlerden işletmelerin görüşleri alınmıştır. Elde edilen bulgular ve öneriler çalışmanın sonuç kısmında verilmiştir.Yayın Performance analysis in Turkish banking sector. Camels application(Işık Üniversitesi, 2020-01-15) Koç, Caner; Teker, Dilek; Işık Üniversitesi, Sosyal Bilimler Enstitüsü, Yöneticiler İçin İşletme Yönetimi Yüksek Lisans ProgramıAfter funds suppliers and funds demanders Banks are 3rd actors in the financial system. The banking sector accounts for most financial intermediaries. Fund transfer, Money supply, economic and financial policies support is some of the main activities. In addition to all its duties within the financial system, it also makes a huge contribution to the employment of the country as a sector. Thus, it has importance and responsibility for all kinds of structures in households, from small to medium-sized enterprises, commercial and corporate companies, to public institutions. All structures will be affected in case of possible crisis that banks will experience. These effects lead to many crises in the country, especially the economic crisis, and may result in serious chaos environments. In order not to experience these situations, the banking sector must be under audit and observation. One of the most important actions to be taken for this audit and observation is the regular measurement of financial performance analysis of banks. CAMELS analysis is a globally accepted system for this performance analysis. Camels analysis measures banks with components of capital adequacy, asset quality, management quality, profitability, liquidity and sensitivity to market risks. In this study, a total of 16 banks, 2 separate bank groups operating in the Turkish banking sector, 13 of which are private capital banks, 3 of which are Public Banks, were subjected to CAMELS analysis for 16 separate periods taking into account the balance sheets at the end of 2003 and 2018. According to the results of the study, among the banks, Türkiye Cumhuriyeti Ziraat Bankası A.Ş., Akbank T.A.Ş. ve Türkiye Garanti Bankası A.Ş. among the groups, it was observed that the group of Public Banks had stronger performance than other banks and groups.Yayın CSR and social marketing as enablers of recovery after the global recession: the Turkish banking industry(IGI Global, 2016-12-21) Gül, Mısra Çağla; Kaytaz, MehmetCorporate Social Responsibility (CSR) is a relatively new concept in Turkey. Leading companies including banks stress socially responsible activities in their marketing communications. The recent economic crisis put banks into the center stage again. Turkey was one of the few countries that emerged from the economic downturn relatively quickly. In the initial stages of the crisis, banks faced some criticism for protecting their self-interest more and not acting for the benefit of the society. Later, these criticisms got weaker and less frequent. This chapter examines the behavior of banks during the crisis with respect to CSR and social marketing. Particularly, the chapter analyzes how the banks behaved during the crisis and how they supported small and medium scale enterprises and local communities through CSR strategies, as well as how they utilized CSR efforts as a marketing tool. In addition, the outcome of these strategies is discussed.Yayın Does everyone benefit equally from self-efficacy beliefs? The moderating role of perceived social support on motivation(Sage Publications Inc, 2018-02) Bağcı Hemşinlioğlu, Sabahat ÇiğdemThis study investigated whether perceived goal support from family and friends may moderate the relationship between academic self-efficacy and motivational outcomes among early adolescent students recruited from a low-middle socio-economic status(SES) background school in Turkey (N = 319, Xa(ge) = 13.13, SD = .80). Self-report questionnaires included measures of academic self-efficacy, perceived family and friend support, and academic and career motivations. Academic self-efficacy and perceived support from family related positively to both types of motivation. Children who perceived lower family support benefited more from the positive effects of self-efficacy on motivations, whereas children with higher family support seemed to gain less (or not gain at all) from self-enhancing functions of self-efficacy. Same findings were found for peer support, but only when family support was excluded from analyses. Findings implied the need to study larger family and peer contexts under which self-efficacy beliefs may be more or less effective on motivation.Yayın Design and analysis of classifier learning experiments in bioinformatics: survey and case studies(IEEE Computer Soc, 2012-12) İrsoy, Ozan; Yıldız, Olcay Taner; Alpaydın, Ahmet İbrahim EthemIn many bioinformatics applications, it is important to assess and compare the performances of algorithms trained from data, to be able to draw conclusions unaffected by chance and are therefore significant. Both the design of such experiments and the analysis of the resulting data using statistical tests should be done carefully for the results to carry significance. In this paper, we first review the performance measures used in classification, the basics of experiment design and statistical tests. We then give the results of our survey over 1,500 papers published in the last two years in three bioinformatics journals (including this one). Although the basics of experiment design are well understood, such as resampling instead of using a single training set and the use of different performance metrics instead of error, only 21 percent of the papers use any statistical test for comparison. In the third part, we analyze four different scenarios which we encounter frequently in the bioinformatics literature, discussing the proper statistical methodology as well as showing an example case study for each. With the supplementary software, we hope that the guidelines we discuss will play an important role in future studies.Yayın 2008 krizi öncesi ve sonrasının Türk bankacılık sektörü üzerindeki etkisi(Işık Üniversitesi, 2018-08-03) Ermiş, Hasanali; Teker, Suat; Işık Üniversitesi, Sosyal Bilimler Enstitüsü, Muhasebe ve Denetim Yüksek Lisans Programı2008 krizi, ABD’de ortaya çıkan ve sonrasında tüm dünyaya yayılan, dünya tarihindeki en büyük krizlerden birisidir. Krizin etkilerini yoğun biçimde gösterdiği sektörlerden birisi de bankacılık sektörüdür. 2008 krizinin öncesinde ve sonrasında Türkiye’deki bankaların performanslarının karşılaştırılması, çalışmanın temel amacı olarak belirlenmiştir. Bu amacın gerçekleşmesi için literatür taraması yöntemi kullanılmıştır. Çalışmada 2008 krizi öncesi ve sonrasında Türk bankacılık sektöründe sermaye yeterlik oranı, kârlılık, özkaynak kârlılığı, aktif kârlılık, net faiz marjı, sorunlu kredi oranları, mevduatların krediye dönüşme oranı göstergeleri, donuk aktif göstergeleri değerlendirmeye alınmıştır. Elde edilen sonuçlara göre kriz kârlılık, aktif kârlılık, özkaynak kârlılığı göstergelerinde düzeyleri değişecek şekilde olumsuz etkiler ortaya koymuştur. 2008 krizinin Türk bankacılık sektöründe sorunlu kredilere olan etkilerinin farklılık meydana getirmeyecek yapıda olduğu görülmüştür. Çalışmada ayrıca donuk aktif ortalamaları ile net faiz marjı göstergelerinin krizle birlikte artış gösterdiği yönünde sonuçlar elde edilmiştir.2001 krizi sonrasında yeniden yapılanan ve nispeten güçlenen Türk bankacılık sektörünün krizin olumsuz etkilerine karşın belirli ölçüde istikrar yakalayarak etkilerin düzeyini azalttığı sonucuna varılmıştır.Yayın A novel biometric identification system based on fingertip electrocardiogram and speech signals(Elsevier Inc., 2022-03) Güven, Gökhan; Güz, Ümit; Gürkan, HakanIn this research work, we propose a one-dimensional Convolutional Neural Network (CNN) based biometric identification system that combines speech and ECG modalities. The aim is to find an effective identification strategy while enhancing both the confidence and the performance of the system. In our first approach, we have developed a voting-based ECG and speech fusion system to improve the overall performance compared to the conventional methods. In the second approach, we have developed a robust rejection algorithm to prevent unauthorized access to the fusion system. We also presented a newly developed ECG spike and inconsistent beats removal algorithm to detect and eliminate the problems caused by portable fingertip ECG devices and patient movements. Furthermore, we have achieved a system that can work with only one authorized user by adding a Universal Background Model to our algorithm. In the first approach, the proposed fusion system achieved a 100% accuracy rate for 90 people by taking the average of 3-fold cross-validation. In the second approach, by using 90 people as genuine classes and 26 people as imposter classes, the proposed system achieved 92% accuracy in identifying genuine classes and 96% accuracy in rejecting imposter classes.Yayın Performance and security issues in e-payment systems: pay on-line case(Işık Üniversitesi, 2006-06) Karahasan, Orhan; Kuru, Selahattin; Işık Üniversitesi, Fen Bilimleri Enstitüsü, Bilgisayar Mühendisliği Yüksek Lisans ProgramıIn this thesis, we report an experience on Performance and Security issues in E-Payment systems. We develop an E-Payment system which covers all introduced performance and security measures written in this thesis. We also compare different types of means that can be used in E-Payment systems. We mentioned different types of network architectures, and their benefits and drawbacks for E-Payment systems. An example e-payment system called Pay ON-LINE is developed with the proposed security and performance architectures. This system is in use in Şile campus of Isik University.
