Preferred Language
Articles
/
VoZ8soYBIXToZYAL47HT
Multi-Channel Distributed DSA Networks: Connectivity and Rendezvous Tradeoffs
...Show More Authors

In this paper, we investigate and characterize the effects of multi-channel and rendezvous protocols on the connectivity of dynamic spectrum access networks using percolation theory. In particular, we focus on the scenario where the secondary nodes have plenty of vacant channels to choose from a phenomenon which we define as channel abundance. To cope with the existence of multi-channel, we use two types of rendezvous protocols: naive ones which do not guarantee a common channel and advanced ones which do. We show that, with more channel abundance, even with the use of either type of rendezvous protocols, it becomes difficult for two nodes to agree on a common channel, thereby, potentially remaining invisible to each other. We model this invisibility as a Poisson thinning process and show that invisibility is even more pronounced with channel abundance. Following the disk graph model, we represent the multiple channels as parallel edges in a graph and build a multi-layered graph (MLG) in R2. In order to study the connectivity, we show how percolation occurs in the MLG by coupling it with a typical discrete percolation. Using a Boolean model and the MLG, we study both cases of primaries' absence and presence. For both cases, we define and characterize connectivity of the secondary network in terms of the available number of channels, deployment densities, number of simultaneous transmissions per node, and communication range. When primary users are absent, we derive the critical number of channels which maintains supercriticality of the secondary network. When primary users are present, we characterize and analyze the connectivity for all the regions: channel abundance, optimal, and channel deprivation. For each region we show the requirement and the outcome of using either type of rendezvous techniques. Moreover, we find the tradeoff between deployment-density versus rendezvous probability which results in a connected network. Our results can be used to decide on the goodness of any channel rendezvous algorithm by computing the expected resultant connectivity. They also provide a guideline for achieving connectivity using minimal resources.

Scopus Clarivate Crossref
Publication Date
Sun Jan 03 2016
Journal Name
Journal Of The College Of Basic Education
Simultaneous determination of cephalexin and cefixime by first and second derivative ultraviolet spectrophotometry
...Show More Authors

Publication Date
Wed Jan 01 2020
Journal Name
Indian Journal Of Forensic Medicine And Toxicology
Mouse hepatocellular carcinoma sensitivity to cisplatin and docetaxel and analysis of related proteins
...Show More Authors

Scopus (1)
Scopus
Publication Date
Mon Dec 01 2025
Journal Name
Al-khwarizmi Engineering Journal
Object Dimension and Location Determination in Gantry Robots and Conveyor Systems: A Review
...Show More Authors

A​‍​‌‍​‍‌ gantry robot is one of the most common types of industrial robots with linear movement. This type of robot is also known as a Cartesian or linear robot. It is an automated industrial system that moves along linear paths, enabling it to create a 3D envelope of the space in which it operates. A robot of this type has a standardised configuration process because it can have several sets of axes, such as X, Y and Z. The gantry robot picks up products from several places, so it can search through various locations. Afterwards, it carefully deposits the products on a conveyor belt for the next stage of the procedure or final ​‍​‌‍​‍‌shipment. This integration enables continuous and automated material flow

... Show More
View Publication Preview PDF
Crossref
Publication Date
Thu Jul 05 2018
Journal Name
Eurasip Journal On Wireless Communications And Networking
Positioning and guiding educational robots by using fingerprints of WiFi and RFID array
...Show More Authors

View Publication
Scopus (7)
Crossref (6)
Scopus Clarivate Crossref
Publication Date
Thu Oct 30 2008
Journal Name
College Of Islamic Sciences
Return in the gift and its contraindications in Islamic jurisprudence and Iraqi law
...Show More Authors

In his life, a person engages in different types of verbal and actual dispositions that result in various effects, some of which are necessary and not valid, such as selling, and some are not necessary for one of the two contracting parties, such as a mortgage or both, such as lending and agency. However, there are some actions that are sometimes necessary and not necessary at other times, such as a gift that indicates in its simplest sense. Owning money for another without compensation, it is one of the doors of benevolence and benevolence, and it is one of the attributes of perfection with which God, may He be glorified and exalted be He, described Himself. - And if this analogy is the difference - and distanced himself from greed, the

... Show More
View Publication Preview PDF
Publication Date
Tue Mar 01 2011
Journal Name
Journal Of Economics And Administrative Sciences
Developing and Sustaining a Multilevel Competitive Learning Organization – A Behavioral and Cognitive Approach
...Show More Authors

To maintain a sustained competitive position in the contemporary environment of  knowledge  economy,  organizations  as an open social systems must have an ability to learn and know  how to adapt to rapid changes  in a proper fashion so that organizational objectives will be achieved efficiently and effectively.  A multilevel approach is adopted proposing that organizational learning suffers from the lack of interest about the strategic competitive performance of the organization. This remains implicit almost in all models of organizational learning and there is little focus on how learning organizations achieve sustainable competitive advantage . A dynamic model that captures t

... Show More
View Publication Preview PDF
Crossref
Publication Date
Mon Sep 30 2024
Journal Name
مجلة جامعة الانبار للعلوم البدنیة والریاضیة
Music and its impact on the sports and military scene of Mesopotamian civilization
...Show More Authors

The ancient Iraqis in the Mesopotamian civilization practiced various sports activities and physical exercises to develop their physical fitness until these practices became a part of their lives and accompanied their religious, social, and military celebrations. Music had a presence in many sports scenes, and the presence of musicians and musical instruments with the armies indicated its great role. In the military scene, the research aims to shed light on the archaeological evidence and evidence of the integration of music with the sports and military scene in Mesopotamian civilization and to explore the impact of music in the sports and military scene of Mesopotamian civilization. The historical approach was adopted in collecting and des

... Show More
View Publication Preview PDF
Crossref
Publication Date
Mon Jul 06 2020
Journal Name
International Journal Of Research In Pharmaceutical Sciences
Obesity and Breast Cancer: Circulating Adipokines and Their Potential Diagnostic as Risk Biomarkers
...Show More Authors

Obesity and cancer are two major epidemics of this century. Obesity is related to a higher risk of many types of cancer. Studies have accessed circulating adipokines, as key-mediators in obesity and breast cancer. The study is aimed to examine the circulating levels of insulin-like growth factor-1, leptin, adiponectin, and resistin in premenopausal Iraqi women with breast cancer. The current study was performed during the period from June 2019 to December 2019 at Oncology unit/ Medical City Hospital-Baghdad. A total of 90 premenopausal women with BC/ stage II and III after 2nd dose of chemotherapy were contributed in this study as patients group. Their ages ranged from (35- 50) years in addition to 90 premenopausal healthy women wer

... Show More
View Publication
Scopus (8)
Crossref (7)
Scopus Crossref
Publication Date
Sun Dec 31 2023
Journal Name
College Of Islamic Sciences
The concept of inconsistency and measuring the inverse relationship between overlap and contrast.
...Show More Authors

 

abstract:

The aim of this study is to clarify the relationship between the concept of  inconsistency and the measurement of the inverse relationship of overlap and contrast. The study will address the following points:

  1. Explaining the true nature of inconsistency and contrast, as understanding their relationship is essential for determining them.
  2. Examining the view of the scholars regarding their significance as approaches to understanding the relationship.
  • Identifying the relationship between inconsistency and contrast in terms of overlap and contrast.

... Show More
View Publication Preview PDF
Publication Date
Mon Dec 30 2019
Journal Name
College Of Islamic Sciences
The biography of the Prophet Muhammad () and his Sunnah between softness and distress
...Show More Authors

The Prophet Muhammed () is distinguished in the history of mankind by the fact that he came with a law that combined these two opposing sides, reality and ideals, a wonderful and amazing collection, and he created a wonderful composition between them, and they used together a wise comprehension to ensure the treatment of its ills, and the reform of their delusions together, and uses both Both of them are in the necessary position of the needs of life, and the contradictions and separation of this collection and the wise harness in this research from his law, may God bless him and grant him peace, which shows us this balance in the system of Islam, the most sincere representation, where it is one of the honors of morality, good appreci

... Show More
View Publication Preview PDF