Contributions to adaptive equalization and timing recovery for optical storage systems

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Pembuatan Program Aplikasi Berbasis Website Pada Yayasan Pouk Bojong Indah, Jakarta

Website is an internet services application much sought after at the moment. The number of users on the website currently utilized by organizations as the media dissemination of information as well as media promotion. The utilization of this website not only carried out by organizations that are non-profit, but there is also a non-profit. One of the organizations that are non-profit and want to make use of the website as a medium of information dissemination is Yayasan Persekutuan Oikoumene Umat Kristen (POUK) Bojong Indah. The methodology used in this software development is a method of prototyping. The reason the use of prototyping model this is because the application can be done easily. People who need an application knowing what to expect in the application program, and save time in the development of the system. This website-based application program will be created using the programming language PHP and Javascript. The management of the database on this website-based applications use MySQL with Apache as the server software. The purpose of the creation of application programs based on website yayasan POUK Bojong Indah is to help Yayasan POUK Bojong Indah in distributing information relating to the schedule of activities, news about Yayasan POUK Bojong Indah, profils, and activities undertaken

Near minimum bit-error rate equalizer adaptation for PRML systems

Receivers for partial response maximum-likelihood systems typically use a linear equalizer followed by a Viterbi detector. The equalizer tries to confine the channel intersymbol interference to a short span in order to limit the implementation complexity of the Viterbi detector. Equalization is usually made adaptive in order to compensate for channel variations. Conventional adaptation techniques, e.g. LMS, are in general suboptimal in terms of bit-error rate. In this paper we present a new equalizer adaptation algorithm that seeks to minimize bit-error rate at the Viterbi detector output. The algorithm extracts information from the sequenced amplitude margin (SAM) histogram and incorporates a selection mechanism that focuses adaptation on particular data and noise realizations. From a complexity standpoint, the algorithm is as simple as the conventional LMS algorithm. Simulation results, for an idealized optical storage channel, confirm a substantial performance improvement relative to existing adaptation algorithm

Cancellation of linear intersymbol interference for two-dimensional storage systems

This paper discusses the cancellation of linear intersymbol interference (ISI) in two-dimensional (2-D) systems. It develops a theory for the error rate of receivers that use tentative decisions to cancel ISI. It also formulates precise conditions under which such ISI cancellation can be applied effectively. For many 2-D systems, these conditions are easily met, and therefore the application of ISI cancellation is of significant interest. The theory and the conditions are validated by simulation results for a 2-D channel model. Furthermore, results for an experimental 2-D optical storage system show that, for a single-layer disk with a capacity of 50 GB, a substantial performance improvement may be obtained by applying ISI cancellation

Minimum latency tracking of rapid variations in two-dimensional storage systems

The trend of increasing storage densities results in growing sensitivity of system performance to variations of storage channel parameters. To counteract these variations, more adaptivity is needed in the data receiver. Accurate tracking of rapid variations is limited by latencies in the adaptation loops. These latencies are largely governed by delays of the bit detector. In two-dimensional storage systems, data are packaged in a group of adjacent tracks or rows, and for some of the rows the detection delays can increase dramatically with respect to one-dimensional systems. As a result, the effective latencies in the adaptation loops preclude the tracking of rapid variations and really limit the performance of the system. In this paper, a scheme is proposed that overcomes this problem and that can be used for timing recovery, automatic gain control, and other adaptive circuits. Rapid variations for all the rows are tracked using control information from rows for which detector latency is smallest. This works properly if rapid variations are common across the rows as is the case, for example, for the two-dimensional optical storage (TwoDOS) system. Experimental results for TwoDOS confirm that the scheme yields improved performance with respect to conventional adaptation scheme

Studi Eksperimental Karakteristik Beton Dengan Agregat Kasar Daur Ulang Dengan Fc'=25 MPa

Pada studi eksperimental ini, digunakan beton daur ulang dengan agregat kasarnya berasal dari limbah/brangkal benda uji beton di laboratorium. Benda uji silinder digunakan untuk mengetahui sifat mekanik seperti kuat tekan, kuat geser, dan kuat tarik belah. Tiga variasi persentase yang berbeda dari agregat kasar daur ulang digunakan dalam perencanaan campuran dengan fc’ = 25 MPa, yaitu 0%, 50%, dan 100% agregat kasar daur ulang. Hasil pengujian menunjukan nilai kuat tekan karakteristik fc’ = 28.7 MPa dan fc’ = 28.4 MPa untuk masing-masing campuran 50% dan 100% agregat kasar daur ulang. Nilai kuat tarik belah sebesar fct = 2.38 MPa, fct = 2.78 MPa, dan fct = 2.81 MPa untuk 0%, 50%, dan 100% agregat kasar daur ulang. Sedangkan kuat geser fv = 5,55MPa, fv = 4.28 MPa, dan fv = 3.86 MPa untuk 0%, 50%, dan 100% agregat kasar daur ulang

Phase equilibria and phase transformations in the Ti-rich corner of the Fe-Ni-Ti system

While the main features of the Fe-Ni-Ti system are well known at low Ti content, literature review of the Ti-rich corner revealed inconsistencies between experimental reports. This investigation presents new experimental results, defined to remove the uncertainties concerning melting behavior and solid-state phase equilibria of the (Ni,Fe)Ti2 phase with the adjacent (Fe,Ni)Ti (B2, CsCl-type structure) and Beta-Ti (A2, W-type) phases. Six samples have been prepared and examined by differential thermal analysis performed in yttria and alumina crucibles, and by scanning electron microscopy in the as-cast state as well as equilibrated at 900°C