Multiple Access for Massive Machine Type Communications

The internet we have known thus far has been an internet of people, as it has connected people with one another. However, these connections are forecasted to occupy only a minuscule of future communications. The internet of tomorrow is indeed: the internet of things. The Internet of Things (IoT) promises to improve all aspects of life by connecting everything to everything. An enormous amount of effort is being exerted to turn these visions into a reality. Sensors and actuators will communicate and operate in an automated fashion with no or minimal human intervention. In the current literature, these sensors and actuators are referred to as machines, and the communication amongst these machines is referred to as Machine to Machine (M2M) communication or Machine-Type Communication (MTC). As IoT requires a seamless mode of communication that is available anywhere and anytime, wireless communications will be one of the key enabling technologies for IoT. In existing wireless cellular networks, users with data to transmit first need to request channel access. All access requests are processed by a central unit that in return either grants or denies the access request. Once granted access, users' data transmissions are non-overlapping and interference free. However, as the number of IoT devices is forecasted to be in the order of hundreds of millions, if not billions, in the near future, the access channels of existing cellular networks are predicted to suffer from severe congestion and, thus, incur unpredictable latencies in the system. On the other hand, in random access, users with data to transmit will access the channel in an uncoordinated and probabilistic fashion, thus, requiring little or no signalling overhead. However, this reduction in overhead is at the expense of reliability and efficiency due to the interference caused by contending users. In most existing random access schemes, packets are lost when they experience interference from other packets transmitted over the same resources. Moreover, most existing random access schemes are best-effort schemes with almost no Quality of Service (QoS) guarantees. In this thesis, we investigate the performance of different random access schemes in different settings to resolve the problem of the massive access of IoT devices with diverse QoS guarantees. First, we take a step towards re-designing existing random access protocols such that they are more practical and more efficient. For many years, researchers have adopted the collision channel model in random access schemes: a collision is the event of two or more users transmitting over the same time-frequency resources. In the event of a collision, all the involved data is lost, and users need to retransmit their information. However, in practice, data can be recovered even in the presence of interference provided that the power of the signal is sufficiently larger than the power of the noise and the power of the interference. Based on this, we re-define the event of collision as the event of the interference power exceeding a pre-determined threshold. We propose a new analytical framework to compute the probability of packet recovery failure inspired by error control codes on graph. We optimize the random access parameters based on evolution strategies. Our results show a significant improvement in performance in terms of reliability and efficiency. Next, we focus on supporting the heterogeneous IoT applications and accommodating their diverse latency and reliability requirements in a unified access scheme. We propose a multi-stage approach where each group of applications transmits in different stages with different probabilities. We propose a new analytical framework to compute the probability of packet recovery failure for each group in each stage. We also optimize the random access parameters using evolution strategies. Our results show that our proposed scheme can outperform coordinated access schemes of existing cellular networks when the number of users is very large. Finally, we investigate random non-orthogonal multiple access schemes that are known to achieve a higher spectrum efficiency and are known to support higher loads. In our proposed scheme, user detection and channel estimation are carried out via pilot sequences that are transmitted simultaneously with the user's data. Here, a collision event is defined as the event of two or more users selecting the same pilot sequence. All collisions are regarded as interference to the remaining users. We first study the distribution of the interference power and derive its expression. Then, we use this expression to derive simple yet accurate analytical bounds on the throughput and outage probability of the proposed scheme. We consider both joint decoding as well as successive interference cancellation. We show that the proposed scheme is especially useful in the case of short packet transmission

Exploring the Glycolytic Enzymes, Glucose-6-phosphate isomerase (CpGPI) and Hexokinase (CpHK) as Potential Drug Targets in Cryptosporidium parvum

Cryptosporidium parvum is a water-borne and food-borne apicomplexan pathogen. It is one of the top four diarrheal-causing pathogens in children under the age of five in developing countries, and an opportunistic pathogen in immunocompromised individuals. The preventative measures are not fully effective with, nitazoxanide (NTZ), the only FDA-approved drug for use in immunocompetent individuals. Unlike other apicomplexans, C. parvum lacks Kreb’s cycle and cytochrome-based respiration, thus relying mainly on glycolysis to produce ATP. In this study, we characterized the primary biochemical features of the C. parvum glucose-6-phosphate isomerase (CpGPI) and determined its Michaelis constant towards fructose-6-phosphate (Kvm = 0.309 mM, Vvmax = 31.72 nmol/μg/min). We also discovered that ebselen, an organoselenium drug, was an inhibitor of CpGPI by high-throughput screening of 1,200 known drugs. Ebselen acted on CpGPI as an allosteric noncompetitive inhibitor (ICv50 = 8.33 μM), while complete inhibition of CpGPI activity was not achieved. Although ebselen is useful in studying the inhibition of CpGPI enzyme activity, further proof is needed to chemically and/or genetically validate CpGPI as a drug target. We also identified four drugs as CpHK inhibitors with micromolar level of anti-cryptospordial activities at concentrations nontoxic to the host cells (i.e., hexachlorphene, thimerosal, alexidine dihydrochloride and ebselen with ECv50 = 0.53, 1.77, 8.1 and 165 μM, respectively). The anti-CpHK activity of the four existing drugs provided us new reagents for studying the enzyme properties of the parasite hexokinase. We have previously observed that 2-deoxy-D-glucose (2DG) could inhibit both the enzyme activity of C. parvum hexokinase (CpHK) and the parasite growth in vitro. However, the action and fate of 2DG in C. parvum was not fully investigated. In the present study, we showed that, although 2DG could be phosphorylated by CpHK to form 2DG-6-phosphate (2DG6P), the anti-cryptosporidial activity of 2DG was mainly attributed to the action of 2DG on CpHK, rather than the action of 2DG or 2DG6P on the downstream enzyme CpGPI, nor 2DG6P on CpHK. These observations further supported the hypothesis that CpHK could serve as a drug target in the parasite

Channel estimation scheme for 3.9G wireless communication systems using RLS algorithm

Main challenges for a terminal implementation are efficient realization of the receiver, especially for channel estimation (CE) and equalization. In this paper, training based recursive least square (RLS) channel estimator technique is presented for a long term evolution (LTE) single carrier-frequency division multiple access (SC-FDMA) wireless communication system. This CE scheme uses adaptive RLS estimator which is able to update parameters of the estimator continuously, so that knowledge of channel and noise statistics are not required. Simulation results show that the RLS CE scheme with 500 Hz Doppler frequency has 3 dB better performances compared with 1.5 kHz Doppler frequency

Low complexity MMSE based channel estimation technique for LTE OFDMA systems

Long term evolution (LTE) is designed for high speed data rate, higher spectral efficiency, and lower latency as well as high-capacity voice support. LTE uses single carrierfrequency division multiple access (SC-FDMA) scheme for the uplink transmission and orthogonal frequency division multiple access (OFDMA) in downlink. The one of the most important challenges for a terminal implementation are channel estimation (CE) and equalization. In this paper, a minimum mean square error (MMSE) based channel estimator is proposed for an OFDMA systems that can avoid the ill-conditioned least square (LS) problem with lower computational complexity. This channel estimation technique uses knowledge of channel properties to estimate the unknown channel transfer function at non-pilot subcarriers.<br /

Political Instability and Lessons for Pakistan: Case Study of 2014 PTI Sit in/Protests

Abstract. It’s a short allegory to present the case for the importance of Political stability in the economic progress of a country. The Arab spring protests were seen as strengthening democracy in the Arab world. Notwithstanding the surprise Arab spring brought in shape of further destabilizing Middle East, a similar environment of unrest and protests in a practicing democracy like Pakistan capture same dynamics of uncertainty that dampen economic destabilization. The paper briefly covers PTI’s sit in protests in year 2014 to make a case for how political instability stifled economic progress in Pakistan though momentarily.Keywords. Political economy, Pakistan economy.JEL. D72, F59, P16

Biofuels (Bioethanol, Biodiesel,and Biogas) from Lignocellulosic Biomass :A Review

الانبعاثات الغازية الناتجة عن استخدام الوقود الأحفوري عند حرقها تسبب زيادة في الاحتباس الحراري. لذلك، من أجل التنمية المستدامة، ينبغي إيلاء الاعتبار لإنتاج طاقات بديلة خضراء يمكن إنتاجها من المخلفات الحيوية المتاحة من مخلفات الطعام أو المخلفات الزراعية أو مخلفات مصانع الأغذية. يعد تحويل النفايات إلى طاقات بديلة أو وقود حيوي جانبًا إيجابيًا نظرًا للزيادة المستمرة في النفايات التي تخلق مشاكل بيئية. ان الأساليب التقليدية للتخلص من النفايات مثل مدافن النفايات أو الحرق تنتج غازات الاحتباس الحراري. إنتاج الوقود الحيوي من مواد اللجينية الخلوية التي تحتوي على بوليمرات الكربوهيدرات واللجنين المكونين اللذان يعتبران بمثابة وسيط لإنتاج المواد الكيميائية والوقود الحيوي والبيوميثان وهيدروجين حيوي كبدائل للوقود الأحفوري. في هذا المقال، قمنا بمراجعة طرق المعالجة المختلفة والتقنية الحديثة التي يمكن لها ان تحسن التحلل للكتلة الحيوية السليلوزية المختلفة (النفايات الزراعية، مخلفات الطعام، النفايات البلدية، ومخلفات الحيوانات في) وتحويلها إلى وقود حيوي (الإيثانول، الديزل الحيوي، الغاز الحيوي). يتم اعتماد اختيار المعالجة المسبقة للمواد السليلوزية على التكلفة الاقتصادية لإنتاج الوقود الحيوي، وقد اجريت العديد من الدراسات في جميع أنحاء العالم من اجل تطوير تكنولوجيا إنتاج الطاقة البديلة (الوقود الحيوي) كبديل للوقود الأحفوري عن طريق تقليل التكلفة الاقتصادية لمعالجة النفايات البيولوجية.Gaseous emissions are from the use of fossil fuels when burned to cause an increase in global warming. Therefore, for sustainable development, consideration should be given to the production of green alternative energies that can be produced from the bio-waste available from food residues, agricultural residues or food factory residues. Converting waste to alternative energies or biofuels is a positive aspect due to the continuous increase in waste that creates environmental problems and traditional methods of waste disposal such as landfills or incineration produce gas.&nbsp; Biofuels production from lignocelluloses materials which are containing carbohydrate polymers and lignin, both of these components considered as a feedstock for produce chemical material, biofuel, biomethane, biohydrogen as alternatives of fossil fuel.&nbsp; In this paper, the researcher reviewed different pretreatments methods and recent technology that can be enhanced degradable of various biowaste or lignocelluloses biomass (agricultural waste, food residue, municipal wastes, and animal waste of) and conversion to biofuel (bioethanol, biodiesel, and biogas). The selection of the pretreatment of cellulosic material depends on the economic cost of producing biofuels; so many researchers around the world were trying to develop alternative energy (biofuel) production technology as an alternative to fossil fuels by reducing the economic cost of biowaste pretreatment

The Effect of Coconut Powder on Asphalt Binder Performance under Laboratory Conditions

Bituminous concrete mixture is the most widely used structural layer in flexible pavements. The surface layer of the paving is exposed to repeated loads in addition to changes in temperature, especially during the summer, when the temperature approaches the softness point of the asphalt binder, and therefore, it is subject to multiple types of failure, especially rutting. The properties of asphalt binder and asphalt mixtures can be improved by using various additives. Coconut shell powder, made from the dried husk of coconut fruit, is a popular addition in many industries. As a result of its high strength and stability, this waste material can be recycled into functional structural components such as composite material reinforcement. This study was conducted to evaluate the performance of coconut husk as very fine particles passing through sieve number 200 (0.075 mm) to modify the asphalt binder. The modifier was added at rates of (0, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10) by the weight of asphalt binder. Two asphalt binder types, 80/100 and 40/50 penetration grade, were used in this study. All asphalt samples were tested for penetration, softening point, rotational viscosity, and dynamic shear rheology. The results showed that the modified samples had better physical and rheological properties compared to the base asphalt binders. However, (7-8%) replacement of coconut husk powder, regardless of the base asphalt binder, yielded the best performance among the modified binders. In conclusion, coconut powder has significant potential as a road-building material due to its impact on the viability of the road construction secto

Antibacterial Activity of Chitosan Extracted from Mucor rouxii

Mucor rouxii was selected due to the high biomass production and significant quantities of chitosan in its cell walls. M. rouxii cultured in Potato dextrose Broth for 96 hrs. at 30 C◦ in a shaking incubator at 150 rpm and 5.5 pH, then the fungal mycelial were dried, grounded and weighted. Mycelial dry weight in total was 68.8g with a yield of 1.72 ± 0.25 g/500ml, chitosan was extracted using the classic chemical method followed by precipitation of chitosan by using sodium hydroxide. chitosan yield was 2.13%, The degree of deacetylation of chitosan extracted from M. rouxii was 82.22% with low Molecular weight 63.67 kDa. The Antimicrobial properties of extracted chitosan was studded on four pathogenic bacteria by MIC method the most resistant strains which were S. aureus, whereas the most vulnerable strains were A. baumannii and E. coli. to produce natural chitosan and replace old sources (crustaceans). The observed antimicrobial properties also indicate an acceptable effect of chitosan on some strains that needs further study

Quantum Organizations with Islamic Way Forward

Firstly, this paper describes a phenomenon of transnational organization and general condition of world and ‘man in the world’. For developing a comprehensive framework, it presents authentic literature review beginning from modernity to post modernity using the hermeneutic-interpretivism research tradition to show the similarities between modernism and post modernism. By revealing the missing link in the quantum paradigm of ralph Kilmann (scholar of quantum organization) on one hand, it develops the possibility of reviving revealed knowledge back into the main frame knowledge of organization theory, on the other hand. By raising and addressing the question of how can the revealed knowledge addresses the current economic dilemma, the paper describes the three lenses available used to understand natural world, socio economic world and behavioral world in Newtonian verses quantum assumptions on organization theory&nbsp;&nbsp; along with their implications. For cross fertilization of ideas and better understanding of God, cosmos and human it presents an alternative of Islamic way forward suggested by scholarly views from East and West. To further substantiate, it presents the stunning insights from the renowned wisdom traditions (pragmatic civilizations) to highlight why religions matter to show (the levels of reality and levels of selfhood as well as relationship between Necessity being and contingent being), responding the situation of power and domination prevalent in organizing world by suggesting historical/civilizational ethical mode and adopting psycho, spiritual-pragmatic approach with holistic world view (Big picture)