No description available.

Motion estimation and motion compensation comprise one of the most important compression methods for video communications. We propose a low-power design of a motion estimation block for a low bit-rate video codec standard H.263. Since the motion estimation is computationally intensive to result in large power consumption, a low-power design is essential for portable or mobile systems. Our block employs the Four-Step Search (4SS) method as its primary algorithm. The design and the algorithm have been optimized to provide adequate results for low-quality video at low-power consumption. The model is developed in VHDL and synthesized using a 0.35 um CMOS library. Power consumption of both gate-level circuits and memory-accesses have been considered. Gate-level simulation shows the proposed design offers a 38% power reduction over a "baseline" implementation of a 4SS model and a 60% power reduction over a baseline Three-Step Search (TSS) model. Power savings through reduction of memory access is 26% over the TSS model and 32% over the 4SS model. The total power consumption of the proposed motion estimation block ranges from 7 - 9 mW and is dependent on the type of video being motion estimated. / Master of Science

The significance of Holy Saturday, the day between Good Friday and Easter Sunday, is often ignored in Christian life. The most influential modern theologian who has taken its importance seriously is the Swiss Catholic theologian, Hans Urs von Balthasar. He has presented a very innovative but also controversial interpretation that on Holy Saturday Jesus Christ suffered in utter solidarity with the dead in Hell and took to himself our self-damnation. However, this interpretation and several other aspects of his theology related to it seem to depart from the traditional teaching in an idiosyncratic way and have invited various critiques. What this thesis aims to do is to critically examine Balthasar’s theology of Holy Saturday and present its implications for Christian suffering and discipleship, while doing full justice to the genre within which he is working (a combination of theology and spirituality) and at the same time taking into consideration the main critiques made against him. First of all, we will argue that Balthasar does not try to present a radical reinterpretation of the doctrine of the Descent into Hell in contrast to the traditional teachings but rather tries to fully appreciate the in-betweenness of Holy Saturday as the day of transition from the Cross to the Resurrection, in other words, from the old aeon to the new. Balthasar says that Christ Himself descended into Hell as victor over sin and death objectively, but He still had to wait for the victory to arrive subjectively. Further, we will claim that this silent waiting on Holy Saturday, which marks the transition from the Cross to the Resurrection, helps us to deepen our understanding of the meaning of suffering in Christian discipleship. The waiting on Holy Saturday represents the fundamentally ‘tragic’ state of the Christian (understood as “tragedy under grace”) torn between the law of this world and the truth of Christ. As a paradoxical being in transition, the Christian believes that their victory is both already there and not there yet. In this sense, the Christian still lives in Holy Saturday. This notion deepens our understanding of suffering in the Christian life, because now we could translate the meaning of suffering into ‘tragic waiting,’ while fully facing the subjective reality of suffering and at the same time maintaining the hope of finding its salvific meaning by relating it to the paschal mystery. Our conclusion will be that this ‘tragic waiting,’ which itself is our lives, now can be seen in a Christological light. In short, we can patiently endure our Holy Saturday because of Christ’s Holy Saturday in Hell.

The use of digitized information is rapidly gaining acceptance in bio-medical applications. Video compression plays an important role in the archiving and transmission of different digital diagnostic modalities. The present scheme of video compression for low bit-rate networks is not suitable for medical video sequences. The instability is the result of block artifacts resulting from the block based DCT coefficient quantization. The possibility of applying deformable motion estimation techniques to make the video compression standard (H.263) more adaptable for bio-medial applications was studied in detail. The study on the network characteristics and the behavior of various congestion control mechanisms was used to analyze the complete characteristics of existing low bit rate video compression algorithms. The study was conducted in three phases. The first phase involved the implementation and study of the present H.263 compression standard and its limitations. The second phase dealt with the analysis of an external force for active contours which was used to obtain estimates for deformable objects. The external force, which is termed Gradient Vector Flow (GVF), was computed as a diffusion of the gradient vectors associated with a gray-level or binary edge map derived from the image. The mathematical aspect of a multi-scale framework based on a medial representation for the segmentation and shape characterization of anatomical objects in medical imagery was derived in detail. The medial representations were based on a hierarchical representation of linked figural models such as protrusions, indentations, neighboring figures and included figures--which represented solid regions and their boundaries. The third phase dealt with the vital parameters for effective video streaming over the internet in the bottleneck bandwidth, which gives the upper limit for the speed of data delivery from one end point to the other in a network. If a codec attempts to send data beyond this limit, all packets above the limit will be lost. On the other hand, sending under this limit will clearly result in suboptimal video quality. During this phase the packet-drop-rate (PDR) performance of TCP(1/2) was investigated in conjunction with a few representative TCP-friendly congestion control protocols (CCP). The CCPs were TCP(1/256), SQRT(1/256) and TFRC (256), with and without self clocking. The CCPs were studied when subjected to an abrupt reduction in the available bandwidth. Additionally, the investigation studied the effect on the drop rates of TCP-Compatible algorithms by changing the queuing scheme from Random Early Detection (RED) to DropTail.

In this study, a new method is proposed to protect JPEG still images through encryption by employing integer-to-integer transforms and frequency domain scrambling in DCT channels. Different from existing methods in the literature, the encrypted image can be further compressed, i.e. transcoded, after the encryption. The method provides selective encryption/security level with the adjustment of its parameters. The encryption method is tested with various images and compared with the methods in the literature in terms of scrambling performance, bandwidth expansion, key size and security. Furthermore this method is applied to the H.263 video sequences for the encryption of I-frames.

Video transmission over noisy wireless channels leads to errors on video, which degrades the visual quality notably and makes error concealment an indispensable job. In the literature, there are several error concealment techniques based on estimating the lost parts of the video from the available data. Utilization of data hiding for this problem, which seems to be an alternative of predicting the lost data, provides a reserve information about the video to the receiver while unchanging the transmitted bit-stream syntax / hence, improves the reconstruction video quality without significant extra channel utilization. A complete error resilient video transmission codec is proposed, utilizing imperceptible embedded information for combined detecting, resynchronization and reconstruction of the errors and lost data. The data, which is imperceptibly embedded into the video itself at the encoder, is extracted from the video at the decoder side to be utilized in error concealment. A spatial domain error recovery technique, which hides edge orientation information of a block, and a resynchronization technique, which embeds bit length of a block into other blocks are combined, as well as some parity information about the hidden data, to conceal channel errors on intra-coded frames of a video sequence. The errors on inter-coded frames are basically recovered by hiding motion vector information along with a checksum into the next frames. The simulation results show that the proposed approach performs superior to conventional approaches for concealing the errors in binary symmetric channels, especially for higher bit rates and error rates.

No description available.

Bcl-2 family members are important regulators of apoptosis, and their tampered expression is often involved in oncogenesis. Of particular importance are the levels of Bcl-2 family members in forming lymphomas. We studied two groups of murine thymic T cell lymphomas derived from either Bcl-2 or Bax overexpression in order to predict their sensitivity and resistance to treatments. While the growth rate and histological characteristics were similar for both lymphoma groups, Bax-derived lymphomas failed to undergo cell cycle arrest following radiation treatment and had frequent p53 mutations. In contrast, Bcl-2-derived lymphomas often halted proliferation following radiation delivery and rarely had p53 mutations. Bax-derived lymphomas were uniformly sensitive to treatment with 2-deoxy-D-glucose (2DG) while all Bcl-2-derived lymphomas were resistant. This led us to hypothesize that the Bcl-2 family is involved in 2DG-induced cell death. Focusing on the mechanism of 2DG toxicity in Bax-derived lymphomas, our studies demonstrate the following: cell death involved the activation of proapoptotic Bax, was effectively blocked by anti-apoptotic Bcl-2, and was mediated, at least in part, by the BH3-only family member Bim. Based on these results, we explored whether a BH3 mimetic (ABT-737) could sensitize lymphomas to 2DG killing. Indeed, a combination of ABT-737 with 2DG enhanced killing in Bax-derived lymphomas and resensitized Bcl-2-overexpressing lymphomas to 2DG. Since both 2DG and BH3 mimetics are currently in clinical trials, understanding their killing mechanisms and optimal combinations are of potential clinical significance. The work in this dissertation demonstrates a novel role of Bcl-2 family member proteins in regulating 2DG toxicity and may predict response to 2DG treatment. The information found presents a new strategy of combining 2DG with BH3 mimetics to improve existing lymphoma therapies.

This diploma thesis deals with the issue of electroerosion machining of materials used in the aerospace industry. The introductory part presents the layout of aerospace materials and the methods by which they can be machined. The next chapter describes the basic principles of EDM. The experimental part is focused on electroerosive cutting of NIMONIC 263 alloy. The greatest emphasis was placed on determining the influence of the cutting wire material on the rate of contamination of the surface layer of the workpiece. The quality of the machined surface was assessed depending on the used wire and the selected machining parameters.

The aim of this master's thesis is experimental electric discharge sinking of special materials for the aerospace industry. The first part is a general overview regarding the technology of electric discharge machining with emphasis on electric discharge sinking. Following this is a practical part devoted to the electric discharge sinking of the Nimonic 263 material with a copper tool electrode with a subsequent evaluation of surface and subsurface changes in this material. The wear of the tool electrode is also examined with the conclusion highlighting combination of machined material and tool electrode material behave in different working conditions and how the surface layer of machined material is affected.