A fast-initializing digital equalizer with on-line tracking for data communications

A theory is developed for a digital equalizer for use in reducing intersymbol interference (ISI) on high speed data communications channels. The equalizer is initialized with a single isolated transmitter pulse, provided the signal-to-noise ratio (SNR) is not unusually low, then switches to a decision directed, on-line mode of operation that allows tracking of channel variations. Conditions for optimal tap-gain settings are obtained first for a transversal equalizer structure by using a mean squared error (MSE) criterion, a first order gradient algorithm to determine the adjustable equalizer tap-gains, and a sequence of isolated initializing pulses. Since the rate of tap-gain convergence depends on the eigenvalues of a channel output correlation matrix, convergence can be improved by making a linear transformation on to obtain a new correlation matrix

Networking DEC and IBM computers

Local Area Networking of DEC and IBM computers within the structure of the ISO-OSI Seven Layer Reference Model at a raw signaling speed of 1 Mops or greater are discussed. After an introduction to the ISO-OSI Reference Model nd the IEEE-802 Draft Standard for Local Area Networks (LANs), there follows a detailed discussion and comparison of the products available from a variety of manufactures to perform this networking task. A summary of these products is presented in a table

Orthogonal Pseudo-Random Sequence Enabled Cognitive and Emergency Communications

With the ever-increasing demands for the broadband mobile communications, it is becoming more and more difficult to accommodate all existing and emerging wireless services and applications due to the limited communication resources particularly radio spectrum. In addition, system parameters of wireless communications often need to be adapted due to the variation of channel characteristics and user demands. Cognitive communication is emerged as an effective technique, particularly to improve the utilization rate of limited communication resources adaptively according to the change in its operating conditions and requirements. To handle these challenges efficiently and reliably in cognitive radio scenario, cyclic prefix (CP) of the OFDM system is precoded in this thesis using pseudo-random sequence. This signaling link can effectively carry transmission parameters and system adaptation information. In first part of the thesis, mutual interference minimization and transmission power adaptation enabled by the additional signaling link are also investigated. In order to make use of this precoded cyclic prefix (PCP) signaling link, an efficient demodulation scheme is needed to reduce the implementation complexity. Therefore, a low complexity signaling demodulator along with a multipath combining technique to further improve the performance in real communication scenario like in multipath channel is proposed in the thesis. The final aspect of this thesis is the investigation of a robust communication system using digital television (DTV) transmitter identification watermark signal which is also a modulated pseudo-random sequence. The previous study on PCP signaling is thus extended to an emergency communication system using DTV watermark. It is found that watermark based communication system is more robust than the DTV broadcasting and can reach a much wider coverage with significantly increased network reliability, which is suitable for national emergency situations

Tantangan Teknis Implementasi DVB-T2 di Indonesia

Transisi dari penyiaran analog ke digital yang menjanjikan banyak kesempatan baru telah memotivasi Organisasi Telekomunikasi Internasional (International Telecommunication Union atau ITU) untuk memberikan dorongan yang besar kepada Negara-negara di dunia untuk segera mewujudkannya. Sebagian besar Negara-negara di dunia juga sudah menyadari begitu pentingnya transisi tersebut. Akan tetapi, banyak tantangan yang membuat proses transisi berlangsung relatif lambat, termasuk di Indonesia. Penelitian ini memilih Swedia dan Inggris yang sudah terlebih dulu melakukan transisi total ke penyiaran digital untuk menggali tantangan-tantangan teknis dan USAha yang dilakukan untuk menghadapi tantangan tersebut. Penelitian ini menganalisa status transisi Indonesia saat ini dan menghasilkan rekomendasi- rekomendasi

Security risks in IP telephony

This paper deals with VoIP communication security and various techniques of VoIP attacks. We divided these threats in several categories according to their specific behaviour and their impact on the affected system. We also tried to find effective methods to prevent or mitigate these attacks. We focused our work on Spam over Internet Telephony (SPIT) as a real threat for the future. We have developed both a tool generating SPIT attacks and AntiSPIT tool defending communication systems against SPIT attacks. AntiSPIT represents an effective protection based on statistical blacklist and works without participation of the called party which is a significant advantage

Tantangan Teknis Implementasi DVB-T2 di Indonesia

Transisi dari penyiaran analog ke digital yang menjanjikan banyak kesempatan baru telah memotivasi Organisasi Telekomunikasi Internasional (International Telecommunication Union atau ITU) untuk memberikan dorongan yang besar kepada Negara-negara di dunia untuk segera mewujudkannya. Sebagian besar Negara-negara di dunia juga sudah menyadari begitu pentingnya transisi tersebut. Akan tetapi, banyak tantangan yang membuat proses transisi berlangsung relatif lambat, termasuk di Indonesia. Penelitian ini memilih Swedia dan Inggris yang sudah terlebih dulu melakukan transisi total ke penyiaran digital untuk menggali tantangan-tantangan teknis dan usaha yang dilakukan untuk menghadapi tantangan tersebut. Penelitian  ini  menganalisa status transisi Indonesia saat ini dan menghasilkan rekomendasi- rekomendasi

Dynamic Interdomain Network Slicing for verticals in the 5Growth project

Proceedings of: IEEE Conference on Network Function Virtualization and Software Defined Networks (NFV-SDN), 9-11 Nov. 2021, Heraklion, Greece.This paper proposes and validates a Interdomain Network Slicing framework for verticals, allowing them to directly participate in the establishment and control of end-to-end Communication Services deployment across multiple inter-operator domains. The framework progresses the means made available by different standards and research initiatives to enhance service requesting and provisioning interfaces for the stakeholders involved, namely operators and verticals. The framework is validated under two different use cases, showcasing effective end-to-end service instantiation and a first assessment towards dynamic service modification capability.This work has been supported by EC H2020 5GPPP 5Growth project (Grant 856709)

O-GlcNAcase Fragment Discovery with Fluorescence Polarimetry

The attachment of the sugar N-acetyl-D-glucosamine (GlcNAc) to specific serine and threonine residues on proteins is referred to as protein O-GlcNAcylation. O-GlcNAc transferase (OGT) is the enzyme responsible for carrying out the modification, while O-GlcNAcase (OGA) reverses it. Protein O-GlcNAcylation has been implicated in a wide range of cellular processes including transcription, proteostasis, and stress response. Dysregulation of O-GlcNAc has been linked to diabetes, cancer, and neurodegenerative and cardiovascular disease. OGA has been proposed to be a drug target for the treatment of Alzheimer’s and cardiovascular disease given that increased O-GlcNAc levels appear to exert a protective effect. The search for specific, potent, and drug-like OGA inhibitors with bioavailability in the brain is therefore a field of active research, requiring orthogonal high-throughput assay platforms. Here, we describe the synthesis of a novel probe for use in a fluorescence polarization based assay for the discovery of inhibitors of OGA. We show that the probe is suitable for use with both human OGA, as well as the orthologous bacterial counterpart from <i>Clostridium perfringens</i>, <i>Cp</i>OGA, and the lysosomal hexosaminidases HexA/B. We structurally characterize <i>Cp</i>OGA in complex with a ligand identified from a fragment library screen using this assay. The versatile synthesis procedure could be adapted for making fluorescent probes for the assay of other glycoside hydrolases