834 research outputs found
Condensation Heat Transfer on Geometrically Enhanced Horizontal Tube: A Review
In this chapter, an attempt has been made to present the recent state of knowledge of free‐convection condensation heat transfer on geometrically enhanced tubes. This survey is divided into three sections. The first section concentrates on research on condensate flooding or retention. The second and the third sections cover the experimental and the theoretical work on geometrically enhanced tubes, respectively
Separation Framework: An Enabler for Cooperative and D2D Communication for Future 5G Networks
Soaring capacity and coverage demands dictate that future cellular networks
need to soon migrate towards ultra-dense networks. However, network
densification comes with a host of challenges that include compromised energy
efficiency, complex interference management, cumbersome mobility management,
burdensome signaling overheads and higher backhaul costs. Interestingly, most
of the problems, that beleaguer network densification, stem from legacy
networks' one common feature i.e., tight coupling between the control and data
planes regardless of their degree of heterogeneity and cell density.
Consequently, in wake of 5G, control and data planes separation architecture
(SARC) has recently been conceived as a promising paradigm that has potential
to address most of aforementioned challenges. In this article, we review
various proposals that have been presented in literature so far to enable SARC.
More specifically, we analyze how and to what degree various SARC proposals
address the four main challenges in network densification namely: energy
efficiency, system level capacity maximization, interference management and
mobility management. We then focus on two salient features of future cellular
networks that have not yet been adapted in legacy networks at wide scale and
thus remain a hallmark of 5G, i.e., coordinated multipoint (CoMP), and
device-to-device (D2D) communications. After providing necessary background on
CoMP and D2D, we analyze how SARC can particularly act as a major enabler for
CoMP and D2D in context of 5G. This article thus serves as both a tutorial as
well as an up to date survey on SARC, CoMP and D2D. Most importantly, the
article provides an extensive outlook of challenges and opportunities that lie
at the crossroads of these three mutually entangled emerging technologies.Comment: 28 pages, 11 figures, IEEE Communications Surveys & Tutorials 201
Intracell interference characterization and cluster interference for D2D communication
The homogeneous spatial Poisson point process (SPPP) is widely used for spatial modeling of mobile terminals (MTs). This process is characterized by a homogeneous distribution, complete spatial independence, and constant intensity measure. However, it is intuitive to understand that the locations of MTs are neither homogeneous, due to inhomogeneous terrain, nor independent, due to homophilic relations. Moreover, the intensity is not constant due to mobility. Therefore, assuming an SPPP for spatial modeling is too simplistic, especially for modeling realistic emerging device-centric frameworks such as device-to-device (D2D) communication. In this paper, assuming inhomogeneity, positive spatial correlation, and random intensity measure, we propose a doubly stochastic Poisson process, a generalization of the homogeneous SPPP, to model D2D communication. To this end, we assume a permanental Cox process (PCP) and propose a novel Euler-Characteristic-based approach to approximate the nearest-neighbor distribution function. We also propose a threshold and spatial distances from an excursion set of a chi-square random field as interference control parameters for different cluster sizes. The spatial distance of the clusters is incorporated into a Laplace functional of a PCP to analyze the average coverage probability of a cellular user. A closed-form approximation of the spatial summary statistics is in good agreement with empirical results, and its comparison with an SPPP authenticates the correlation modeling of D2D nodes
Spatial and Social Paradigms for Interference and Coverage Analysis in Underlay D2D Network
The homogeneous Poisson point process (PPP) is widely used to model spatial
distribution of base stations and mobile terminals. The same process can be
used to model underlay device-to-device (D2D) network, however, neglecting
homophilic relation for D2D pairing presents underestimated system insights. In
this paper, we model both spatial and social distributions of interfering D2D
nodes as proximity based independently marked homogeneous Poisson point
process. The proximity considers physical distance between D2D nodes whereas
social relationship is modeled as Zipf based marks. We apply these two
paradigms to analyze the effect of interference on coverage probability of
distance-proportional power-controlled cellular user. Effectively, we apply two
type of functional mappings (physical distance, social marks) to Laplace
functional of PPP. The resulting coverage probability has no closed-form
expression, however for a subset of social marks, the mark summation converges
to digamma and polygamma functions. This subset constitutes the upper and lower
bounds on coverage probability. We present numerical evaluation of these bounds
on coverage probability by varying number of different parameters. The results
show that by imparting simple power control on cellular user, ultra-dense
underlay D2D network can be realized without compromising the coverage
probability of cellular user.Comment: 10 pages, 10 figure
Solutions for the Power Distribution System of Karachi Electric (K- Electric) to Prevent Deaths in Rainy Season
Karachi is the metropolitan city of Pakistan. In rainy or flood season many deaths occurred due to electric shock. For the prevention, we suggest here to K-Electric (Karachi Electric Supply Distribution company) to control death casualties due to electric shock in rainy season. In suggestion paper providing some suggestions to the big power supplier of Karachi (K-Electric) about safety, maintenance, and monitoring for the prevention from deaths occur in metropolitan city due to electric shock. Those deaths occur due to faults in electric pole and touch the fallen live wire. When people touch the pole, they got electric shock in rainy and storm condition due to these electric faults occur in this condition provides enough loss to humans in the form to lose their lives. For the prevention or overcome the loss of life and danger here are giving some suggestions, if do work on following safety, maintenance and monitoring system then get the control on that loss will occur in heavy rain or flood
LTE-advanced self-organizing network conflicts and coordination algorithms
Self-organizing network (SON) functions have been introduced in the LTE and LTEAdvanced standards by the Third Generation Partnership Project as an excellent solution that promises enormous improvements in network performance. However, the most challenging issue in implementing SON functions in reality is the identification of the best possible interactions among simultaneously operating and even conflicting SON functions in order to guarantee robust, stable, and desired network operation. In this direction, the first step is the comprehensive modeling of various types of conflicts among SON functions, not only to acquire a detailed view of the problem, but also to pave the way for designing appropriate Self-Coordination mechanisms among SON functions. In this article we present a comprehensive classification of SON function conflicts, which leads the way for designing suitable conflict resolution solutions among SON functions and implementing SON in reality. Identifying conflicting and interfering relations among autonomous network management functionalities is a tremendously complex task. We demonstrate how analysis of fundamental trade-offs among performance metrics can us to the identification of potential conflicts. Moreover, we present analytical models of these conflicts using reference signal received power plots in multi-cell environments, which help to dig into the complex relations among SON functions. We identify potential chain reactions among SON function conflicts that can affect the concurrent operation of multiple SON functions in reality. Finally, we propose a selfcoordination framework for conflict resolution among multiple SON functions in LTE/LTEAdvanced networks, while highlighting a number of future research challenges for conflict-free operation of SON
Helping students to get better grades in mathematics at the elementary level
The current study is conducted to explore the learning potential of students at the elementary level by using the scaffolding technique. The study aimed to measure the efficiency of the scaffolding teaching method provided to the students at the elementary level. As it was an experimental study, so, no population was defined. The sample was selected from Gov. Girls Higher Secondary SchoolModel Town A, Bahawalpur, Punjab, Pakistan. All 6th classes of this school were included to analyze the effect of scaffolding as an intervention. Retention of learning after 3 months, the provision of scaffolding in comparison to the traditional method was assessed. After the posttest, there was a retention test as the final test from all four groups. Solomon's four-group design was used for this experiment in which there were 40 students in each group and 160 total participants. In the current study, Pretest, posttest, and after 3months retention test was conducted as research tools. To analyze the data, SPSS version 20 one-sample t-test were used to analyze the data. The Data revealed that scaffolding was proved to be a better strategy compared to the control group. Even the results of retention of learning skills were higher than the control group. Students showed good understanding, remembering, and better-solving processes in experimental groups. Study recommended that scaffolding teaching needs a highly structured supervised environment and may be conducted in controlled conditions. It is recommended that in teacher education, the prospective teachers may be prepared in the principles, procedures, and rules of scaffolding. A due consideration may be given to teaching strategies in all teacher education programs in the country as it is an innovative and progressive way of teaching
Why not everybody loves Hofstede? What are the alternative approaches to study of culture?
In these days the Hofstede's work on culture is most quoted in many publications. For scholars and practitioners knowing and having complete understanding of cross cultural dimensions, Hofstede's work plays an important and dynamic role. His observations and analysis gives the full understanding to the readers and as well as authors and scholars. Still such pioneering work faces much criticism by scholars. Some of the scholars appreciated his credible work. Some scholars quote his finding in their research and some ignore it. In our paper, this study concludes all the criticism on hofstede's work. Basically there are two parts of this paper; in first part we discuss the reason why hofstede's work faces criticism and in second part we recommend various other cultural dimensions, which we can use to understand the culture. Research Findings This paper tries to conclude all the dimensions and also suggest the model for understanding the national culture. Key Words Culture, National culture, Hofstede, cross cultural dimension
Effect of Condensate Flow Rate on Retention Angle on Horizontal Low-Finned Tubes
This article is in an Open Access journalThe paper reports experimental results using simulated condensation on
eight horizontal integral finned tubes with different fin spacing but same
root diameter. Condensation was simulated with low approaching zero
vapor velocity of condensate using three liquids (water, ethylene glycol and
R141b) supplied to the tube via small holes between the fins along the top of
the tubes. Controlling parameters of the investigation were fin spacing of
condensation tubes, flow rate of condensate and surface tension to density
ratio of the condensate. The results indicate that the retention angle
(measured from the top of the tube to the position where the inter-fin space
is completely filled with liquid) increases with the increase in fin spacing.
Also, retention angle increases as the density of the condensate increases
but retention angle decreases with increase in surface tension. Interesting
finding is seen as retention angle remains constant with increase in
condensate flow rate, starting from very low (nearly zero) flow rate to the
flow rate at which the tube gets fully flooded. The critical flow rate for eight
tubes of defined fin density against three working fluids is measured.
Results obtained from simulated condensation for almost zero condensate
velocity are in good agreement with earlier data and theoretical model for
retention angle on such tubes
Beta Thalassemia Carriers detection empowered federated Learning
Thalassemia is a group of inherited blood disorders that happen when
hemoglobin, the protein in red blood cells that carries oxygen, is not made
enough. It is found all over the body and is needed for survival. If both
parents have thalassemia, a child's chance of getting it increases. Genetic
counselling and early diagnosis are essential for treating thalassemia and
stopping it from being passed on to future generations. It may be hard for
healthcare professionals to differentiate between people with thalassemia
carriers and those without. The current blood tests for beta thalassemia
carriers are too expensive, take too long, and require too much screening
equipment. The World Health Organization says there is a high death rate for
people with thalassemia. Therefore, it is essential to find thalassemia
carriers to act quickly. High-performance liquid chromatography (HPLC), the
standard test method, has problems such as cost, time, and equipment needs. So,
there must be a quick and cheap way to find people carrying the thalassemia
gene. Using federated learning (FL) techniques, this study shows a new way to
find people with the beta-thalassemia gene. FL allows data to be collected and
processed on-site while following privacy rules, making it an excellent choice
for sensitive health data. Researchers used FL to train a model for
beta-thalassemia carriers by looking at the complete blood count results and
red blood cell indices. The model was 92.38 % accurate at telling the
difference between beta-thalassemia carriers and people who did not have the
disease. The proposed FL model is better than other published methods in terms
of how well it works, how reliable it is, and how private it is. This research
shows a promising, quick, accurate, and low-cost way to find thalassemia
carriers and opens the door for screening them on a large scale.Comment: pages 17, figures
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