Elektronik ve Haberleşme Mühendisliği Bölümü Yayın Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/260

Browse

Filters

2010 - 201972020 - 20231

Settings

Language: search.filters.language.trPublication Index: search.filters.publicationIndex.Scopus

Search Results

Now showing 1 - 8 of 8
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Ber Anaylsis for Super Lorentz-Gaussian Laser Beams Propagating in Turbulent Media
    (Gazi Univ, Fac Engineering Architecture, 2013) Gokce, Muhsin C.; Gökçe, Muhsin Caner; Sari, Filiz; Ozek, Faruk; Elektronik ve Haberleşme Mühendisliği
    In this work, BER-SNR variation of super Lorentz-Gaussian laser beam that propagating horizontally path in turbulent media is analyzed. Using scintillation index which is obtained by extented Huygens-Fresnel principle, BER - SNR value is calculated. Matlab program is used to show BER - SNR variation depending on link distance and beamwidth. To conclude, in short link range, super Lorentz-Gaussian beam is proven to be better link performance superior to commercially available Gaussian beam.
  • Conference Object
    Design of Led Circuit Card for an Off-Road Lamp
    (2010) Yakişir, B.; Çil, Celal Zaim; Çil, C.Z.; Elektronik ve Haberleşme Mühendisliği
    In this study a working lamp used on the working machines is designed by using the LED diodes instead of a halogen bulb. In the design, firstly a LED or a LED array and a proper driver circuit that can provide the required optical power are designed, and the working lamp developed are tested under various conditions. The luminous output values of the designed LED working lamp are compared with those of a commercial working lamp using a halogen bulb. It is evaluated that in automotive applications working lamps using LEDs could be successfully utilized depending on the optical efficacy of the LED used, the designs of the LED driver and the reflector.
  • Conference Object
    Power Consumption of Novel Throughput Improvement Methods
    (2010) Preveze, B.; Preveze, Barbaros; Şafak, A.; Elektrik-Elektronik Mühendisliği
    The novel proposed method as a combination of Time Division Multiple Access (TDMA) and Orthogonal Frequency Division Multiple Access (OFDMA) called Orthogonal Frequency Division Most Congested Access First (OFDMCAF) provides spectrum sharing, buffer management and improves the throughput. In this work the power consumed by activating each cognitive method is analyzed in addition to the throughput improvement provided by each method used with OFDMCAF. It is shown at the end of the analysis that activation of each method also decreases the average power consumption even the same routing algorithm is used in all cases.
  • Conference Object
    Diffraction of Matter Waves in Time by an Absorbing Half-Screen
    (2010) Umul, Y.Z.; Umul, Yusuf Ziya; Elektronik ve Haberleşme Mühendisliği
    In this study, the scattering of matter waves that accompany to the quantum particles by an absorbing half-plane is examined. A quantum shutter, which is opened at an initial time, is proposed to close the semi-infinite complementary aperture of the half-screen. Hence the matter waves, confined in a determined region of space, transmits to the second region by scattering from the semi-infinite aperture. The mathematical expressions of the scattered fields are plotted numerically and interpreted according to the diffraction theory of Young.
  • Article
    Investigation of Factors Affecting Noise Robustness in Voice Activity Detectors
    (Gazi Univ, Fac Engineering Architecture, 2023) Ozaydin, Selma
    In this manuscript, some voice activity detectors (VADs) in the literature were examined in terms of factors affecting their robustness under different acoustic noise conditions and in this context, the changes in detection accuracy rates according to changing noise conditions were tested. In this scope, the effect of situations such as whether the threshold value used in the decision phase in VAD methods is fixed or adaptive, the analysis window is short or long, the use of more than one feature vector together has been evaluated and analyzed comparatively. While three of the four different VAD detectors examined in this manuscript use feature vectors within the short-term analysis window while generating the decision result, one decides according to the measurement result of long-term spectral vectors. The VAD detectors in the article have been tested using the NOIZEUS noisy speech database. Thus, the performance of the analyzed VADs has been evaluated under different acoustic conditions using an extensive database that has already taken place in the literature. During the testing of the analyzed VADs, different input noise speech signals with environmental background noises between [15-0dB] such as restaurant, car, street, or station were tested. Tests were carried out using objective test measurement methods and the detection accuracy rate of each VAD method was measured. The results showed that each method gave different endurance performance in adverse environmental conditions.
  • Conference Object
    Citation - Scopus: 4
    Human Activity Classification Using Vibration and Pir Sensors
    (2012) Yazar, A.; Çetin, A.E.; Töreyin, B.U.
    Fall detection is an important problem for elderly people living independently and people in need of care. In this paper, a fall detection method using seismic and passive infrared (PIR) sensors is proposed. Fast Fourier transform, mel-frequency cepstrum coefficients, and discrete wavelet transform based features are extracted for classification. Seismic signals are classified into "fall" and "not a fall" classes using support vector machines. Once a moving person is detected by the PIR sensor within a region of interest, fall is detected by fusing seismic and PIR sensor decisions. The proposed system is implemented on a standard personal computer and works in real-time. © 2012 IEEE.
  • Conference Object
    Entropy Functional Based Adaptive Decision Fusion Framework
    (2012) Günay, O.; Töreyin, B.U.; Köse, K.; Çetin, A.E.
    In this paper, an entropy functional based online adaptive decision fusion framework is developed for image analysis and computer vision applications. In this framework, it is assumed that the compound algorithm consists of several sub-algorithms, each of which yields its own decision as a real number centered around zero, representing the confidence level of that particular sub-algorithm. Decision values are linearly combined with weights which are updated online according to an active fusion method based on performing entropic projections onto convex sets describing sub-algorithms. It is assumed that there is an oracle, who is usually a human operator, providing feedback to the decision fusion method. A video based wildfire detection system was developed to evaluate the performance of the decision fusion algorithm. © 2012 IEEE.
  • Conference Object
    Comparison of Ant Colony and Fastest Path Algorithms for Fixed and Variable Number of Nodes in Multi-Hop Networks
    (2010) Şafak, A.; Preveze, B.
    In this study, the fastest path algorithm which is known as a routing method from source to destination and Ant colony method which is known to be adaptable to the dynamic changes in the network are compared for average hop counts, power consumption and packet arrival delays by implementing a mobile network simulation. Even the average hop counts for both algorithms reach to almost same value at the simulation results, since it is seen that the fastest path algorithm provides less packet delay and less power consumption with respect to Ant colony algorithm , it is thought that fastest path algorithm may be more useful than Ant colony algorithm for real time voice or video packet transmissions. ©2010 IEEE.