maher ali | Cairo University (original) (raw)

Papers by maher ali

Proceedings 25th Annual IEEE Conference on Local Computer Networks. LCN 2000, 2000

ICC 2001. IEEE International Conference on Communications. Conference Record (Cat. No.01CH37240), 2000

Abstract We investigate the allocation of multicast nodes and formalize it as splitter placement ... more Abstract We investigate the allocation of multicast nodes and formalize it as splitter placement in wavelength-routed networks (SP-WRN) problem. The SP-WRN problem entails the placement of multicast nodes so that the overall network blocking probabilil y is minimized. To gain a ...

Spie Proceedings Series, 2001

ABSTRACT

International Conference on Networking International Conference on Systems and International Conference on Mobile Communications and Learning Technologies, Apr 23, 2006

Deploying Ethernet in the metro domain will require many different upgrades including end-to-end ... more Deploying Ethernet in the metro domain will require many different upgrades including end-to-end QoS guarantees, protection mechanisms and service performance monitoring. In this paper we propose a distributed method to address network failures for Ethernet which restores lost facilities within tens of milliseconds. Recovery algorithm is localized around the point of failure on the spanning tree thus avoiding the disruption of entire network.

Photonic Netw Commun, 2004

This paper addresses the problem of routing and wavelength assignment of bit-rate-differentiated ... more This paper addresses the problem of routing and wavelength assignment of bit-rate-differentiated optical services in a hybrid network. Hybrid optical networks are composed of resources, such as ®ber links and photonic/electronic switches, that vary in their capabilities and transmission qualities. These networks are also responsible for the realization of optical services with varying quality-of-service (QoS) guarantees. In such networks, it is required to have a cost-effective assignment of the optical and electronic resources to these services in order to maximize the revenue of the network operator. This paper deals with optical services that are de®ned according to their tolerance to transmission impairments. We ®rst divide the provisioning problem into two phases: (1) routing and (2) wavelength assignment and regeneration reservation. In the routing phase, a set of k-routes are generated to select from in the second phase, where each route optimizes a speci®c aspect of the problem (e.g., number of hops, maximum accumulated noise, etc.). The second phase, using the information about the resources along each route, attempts at ®nding the best wavelength allocation on that route such that the signal quality meets the service-level agreement (SLA). The second phase also uses the minimum number of regenerator ports on intermediate nodes for the purpose of wavelength translation and signal clean-up. Comparisons of the above scheme with a probing-based method, reveal substantial enhancements to the blocking performance with a maximum running time increase of 60%. In addition, the use of multiple routes provides higher reduction in the blocking probability over single-routing schemes. Moreover, the proposed, non-pessimistic, provisioning approach has a major impact on reducing the regeneration budget of the network.

Transportation Research Record, 2003

Application of wavelet transforms in the detection of underground shal-low cavities is investigat... more Application of wavelet transforms in the detection of underground shal-low cavities is investigated. Wave propagation is simulated through a transient response analysis on an axisymmetric finite element model. Cavities in a homogeneous half-space and a pavement system of a ...

Cmaj Canadian Medical Association Journal Journal De L Association Medicale Canadienne, Sep 15, 1996

Objective: To determine whether anemia is documented and appropriately investigated for iron defi... more Objective: To determine whether anemia is documented and appropriately investigated for iron deficiency in hospitalized elderly people. Design: Retrospective chart review. Setting: Medical clinical teaching unit (CTU) in secondary care hospital in Hamilton, Ont. Participants: Consecutive patients 65 years of age' or older admitted between April 1992 and March 1993. Outcome measures: Proportion of anemic patients for whom documentation was adequate (included in problem list in patient chart) and for whom adequate investigations were performed (measurement of serum ferritin level in anemic patients in whom iron deficiency was suspected, bone-marrow aspiration for those with intermediate probability of iron deficiency after determination of serum ferritin level, and endoscopy of upper or lower gastrointestinal tract, or both, in patients with iron deficiency). Results: Of 183 eligible patients admitted to the CTU 66 (36%) had anemia; in 47 cases (71%) the anemia was documented by house staff or attending physicians. Of the 66 anemic patients 49 had a nonmacrocytic anemia of unknown cause: 26 had their serum ferritin level measured, 5 underwent bonemarrow aspiration, and 21 were referred for gastrointestinal endoscopy. Six of eight patients with probable iron deficiency (i.e., a serum ferritin level that was diagnostic [less than 18 pg/L] or suggestive [ 18 to 45 pg/L]) underwent endoscopy; two were found to have cancer of the stomach or cecum. Only 26 of the 49 patients had adequate investigation. Conclusion: Anemia is common among elderly patients in hospital. However, iron deficiency is underrecognized and underinvestigated.

Department of Electrical Engineering, The City College and The Graduate School and University Cen... more Department of Electrical Engineering, The City College and The Graduate School and University Center of the City University of New York, NY, USA, {antonis, sherif, akhalil, tanvir, gellinas, marend, ali}@ee.ccny.cuny.edu ... Department of Electrical Engineering, Lakehead ...

Abstract In this paper, we introduce the routing of multi-rate traffic (RMT) problem that arises ... more Abstract In this paper, we introduce the routing of multi-rate traffic (RMT) problem that arises in current backbone networks required to carry the new 40 Gb/s traffic streams. The RMT problem is informally defined as the process of finding the best routing which maximizes ...

Surgical Endoscopy, Dec 1, 2002

Virtual reality simulation is effective in training the novice to perform basic laparoscopic skil... more Virtual reality simulation is effective in training the novice to perform basic laparoscopic skills. Using the Minimally Invasive Surgery Training--Virtual Reality (MIST-VR) trainer, 27 honors high school students were tested at the easy level, prospectively randomized to eight training sessions at the easy (group A, n = 14) or medium (group B, n = 13) level, then retested at the easy level. Both groups were statistically similar at baseline. All scores improved significantly (50.1% to 81.3%) over the period of training (p < 0.05). Although the group A scores were significantly better than the group B scores throughout training (p < 0.05), on final testing at the easy level, group B surpassed group A for all the tasks except TransferPlace (p = 0.054). Virtual simulation is an effective laparoscopic training method for the novice, providing significant improvement in skill levels over a relatively short period. More challenging training seems to predict greater improvement over time and better final skill levels.