Ramazan Savas Aygün

Modeling and Management of Fuzzy Information in Multimedia Database Applications

In this paper, we firstly present a conceptual data model for multimedia database applications based on ExIFO2 model. The ExIFO2 data model is chosen as the conceptual model since it handles complex objects along with their uncertain and imprecise properties. We enhanced this conceptual model in order to meet the multimedia data requirements. In addition to uncertain and imprecise information, we present a way of handling relationships among objects of multimedia database applications. Events that might be extracted from video or audio are also considered in this study. Secondly, the conceptual model is mapped to a logical model, which the fuzzy object-oriented data (FOOD) model is chosen, for storing and manipulating the multimedia objects. This mapping is done in a way that it preserves most of the information represented at the conceptual level. Finally, in this study videos of football (soccer) games is selected as the multimedia database application to show how we handle crisp and fuzzy querying and retrieval of fuzzy and crisp data from the database. A program has been developed to draw ExIFO2 schemas and to map the schema to FOOD code automatically.

Improving UDP performance using intermediate QoD-aware hop system for wired/wireless multimedia communication systems

Multimedia communication in wireless networks is challenging due to the inherent complexity and constraints of multimedia data. To reduce the high bandwidth requirement of video streaming, videos are compressed by exploiting spatial and temporal redundancy, thus yielding dependencies among frames as well as within a frame. Unnecessary transmission and maintenance of useless packets in the buffers cause further loss and degrade the quality of delivery (QoD) significantly. In this paper, we propose a QoD-aware hop system that can decide when and which packets could be dropped without degrading QoD. Moreover, the transmission of useless packets causes network congestion and vain payment by the wireless system subscriber. In this paper, we focus on two types of frame discarding policies to maintain QoD: partial frame discarding policy (PFD) and early frame discarding policy (EFD). PFD policy discards the succeeding packets of a frame if a packet of the frame cannot be served. On the other hand, in EFD policy, when it is likely to fail to serve packets of a frame (based on a threshold) the subsequent packets of the frame are discarded. We first provide an analytical study of average buffer occupancy based on these discarding policies and show the closed-form expressions for average buffer occupancy. We then perform our simulations by implementing a Markovian model and measure the frameput (the ratio of number of frames served) rather than the number of packets served. Copyright

TCP traffic control evaluation and reduction over wireless networks using parallel sequential decoding mechanism

The assumption of TCP-based protocols that packet error (lost or damaged) is due to network congestion is not true for wireless networks. For wireless networks, it is important to reduce the number of retransmissions to improve the effectiveness of TCP-based protocols. In this paper, we consider improvement at the data link layer for systems that use stop-and-wait ARQ as in IEEE 802.11 standard. We show that increasing the buffer size will not solve the actual problem and moreover it is likely to degrade the quality of delivery (QoD). We firstly study a wireless router system model with a sequential convolutional decoder for error detection and correction in order to investigate QoD of flow and error control. To overcome the problems along with high packet error rate, we propose a wireless router system with parallel sequential decoders. We simulate our systems and provide performance in terms of average buffer occupancy, blocking probability, probability of decoding failure, system throughput, and channel throughput. We have studied these performance metrics for different channel conditions, packet arrival rates, decoding time-out limits, system capacities, and the number of sequential decoders. Our results show that parallel sequential decoders have great impact on the system performance and increase QoD significantly.

S2S: structural-to-syntactic matching similar documents

Management of large collection of replicated data in centralized or distributed environments is important for many systems that provide data mining, mirroring, storage, and content distribution. In its simplest form, the documents are generated, duplicated and updated by emails and web pages. Although redundancy may increase the reliability at a level, uncontrolled redundancy aggravates the retrieval performance and might be useless if the returned documents are obsolete. Document similarity matching algorithms do not provide the information on the differences of documents, and file synchronization algorithms are usually inefficient and ignore the structural and syntactic organization of documents. In this paper, we propose the S2S matching approach. The S2S matching is composed of structural and syntactic phases to compare documents. Firstly, in the structural phase, documents are decomposed into components by its syntax and compared at the coarse level. The structural mapping processes the decomposed documents based on its syntax without actually mapping at the word level. The structural mapping can be applied in a hierarchical way based on the structural organization of a document. Secondly, the syntactic matching algorithm uses a heuristic look-ahead algorithm for matching consecutive tokens with a verification patch. Our two-phase S2S matching approach provides faster results than currently available string matching algorithms.

Reducing blurring-effect in high resolution mosaic generation

The mosaic generation methods benefit from global motion estimation (GME) methods, which yield almost accurate estimation of motion parameters. However, the generated mosaics are usually more blurred than the original frames due to the image warping stage and errors in motion estimation. The transformed coordinates resulting from GME are generally real numbers whereas images are sampled into integer values. Although GME methods generate proper motion parameters, a slight error in motion estimation may propagate to subsequent mosaic generation steps. We propose a method to generate clearer mosaics from video. The temporal integration of images is performed using the histemporal filter based on the histogram of values within an interval. The initial frame in the video sequence is registered at a higher resolution to generate a high resolution mosaic. Instead of warping of each frame, the frames are warped into the mosaic at intervals. This reduces the blurring in the mosaic.

Modeling and Verification of Interactive Flexible Multimedia Presentations Using PROMELA/SPIN

The modeling and verification of flexible and interactive multimedia presentations are important for consistent presentations over networks. There has been querying tools proposed whether the specification of a multimedia presentation satisfy inter-stream relationships. Since these tools are based on the interval-based relationships, they cannot guarantee the verification in real-life presentations. Moreover, the irregular user interactions which change the course of the presentation like backward and skip are not considered in the specification. Using PROMELA/SPIN, it is possible to verify the temporal relationships between streams using our model allowing irregular user interactions. Since the model considers the delay of data, the author is assured that the requirements are really satisfied.

Interactive multimedia presentation management in distributed multimedia systems

Multimedia presentations are difficult to handle in the existence of user interactions and complex synchronization requirements. We present a synchronization model which can handle both time-based and event-based actions. The model can cope with the VCR-type user interactions. We also give a simple rule-based synchronization specification language which does not complicate as user interactions are allowed.

FocusALL: Focal Stacking of Microscopic Images Using Modified Harris Corner Response Measure

Automated image analysis of microscopic images such as protein crystallization images and cellular images is one of the important research areas. If objects in a scene appear at different depths with respect to the cameras focal point, objects outside the depth of field usually appear blurred. Therefore, scientists capture a collection of images with different depths of field. Focal stacking is a technique of creating a single focused image from a stack of images collected with different depths of field. In this paper, we introduce a novel focal stacking technique, FocusALL, which is based on our modified Harris Corner Response Measure. We also propose enhanced FocusALL for application on images collected under high resolution and varying illumination. FocusALL resolves problems related to the assumption that focus regions have high contrast and high intensity. Especially, FocusALL generates sharper boundaries around protein crystal regions and good in focus images for high resolution images in reasonable time. FocusALL outperforms other methods on protein crystallization images and performs comparably well on other datasets such as retinal epithelial images and simulated datasets.

Optimizing Associative Experimental Design for Protein Crystallization Screening

The goal of protein crystallization screening is the determination of the main factors of importance to crystallizing the protein under investigation. One of the major issues about determining these factors is that screening is often expanded to many hundreds or thousands of conditions to maximize combinatorial chemical space coverage for maximizing the chances of a successful (crystalline) outcome. In this paper, we propose an experimental design method called “Associative Experimental Design (AED)” and an optimization method includes eliminating prohibited combinations and prioritizing reagents based on AED analysis of results from protein crystallization experiments. AED generates candidate cocktails based on these initial screening results. These results are analyzed to determine those screening factors in chemical space that are most likely to lead to higher scoring outcomes, crystals. We have tested AED on three proteins derived from the hyperthermophile Thermococcus thioreducens, and we applied an optimization method to these proteins. Our AED method generated novel cocktails (count provided in parentheses) leading to crystals for three proteins as follows: Nucleoside diphosphate kinase (4), HAD superfamily hydrolase (2), Nucleoside kinase (1). After getting promising results, we have tested our optimization method on four different proteins. The AED method with optimization yielded 4, 3, and 20 crystalline conditions for holo Human Transferrin, archaeal exosome protein, and Nucleoside diphosphate kinase, respectively.

Stationary background generation in mpeg compressed video sequences

The development of the new video coding standard, MPEG- 4, has triggered many video segmentation algorithms that address the generation of the video object planes (VOPs). The background of a video scene is one kind of VOPs where all other video objects are layered on. In this paper, we propose a method for the generation of the stationary background in a MPEG compressed video sequence. If the objects move frequently and all the components of the background are visible in the video sequence, the background macroblocks can be constructed by using Discrete Cosine Transform (DCT) DC coefficients of the blocks. After the generation of the stationary background, the moving objects can be extracted by taking the difference between the frames and the background.