160 research outputs found
Security Measures in Mobile Commerce: Problems and Solutions
Due to the advent of the Internet, electronic business transactions have exploded around the globe. Along with the Internet, wireless technology has exponentially developed as well. Today, new technologies that allow mobile (cellular) phones and other handheld devices to access the Internet have made wireless business transactions possible. This phenomenon is known as mobile commerce or M-Commerce. It has been predicted that the number of mobile phones connected to the mobile Internet will exceed the number of Internet-connected PCs before 2007. The mobile phone will therefore become the most prevalent device for accessing the Internet. Several industry analysts predict that Mcommerce will constitute a multibillion dollar business by 2005. However, M-Commerce brings new challenges in providing information security as information travels through multiple networks often across wireless links. What must be done to secure financial transactions via mobile commerce? Generally speaking, M-Commerce creates more security concerns than traditional E-Commerce. In this paper, security measures in M-Commerce, wireless security, and the application of cryptography for key generation, authentication, digital signature and digital certificate are discussed
METHOD DEVELOPMENT AND VALIDATION OF THE CHROMATOGRAPHIC ANALYSIS OF FLUTICASONE PROPIONATE AND SALMETEROL XINAFOATE COMBINATION IN SOLUTIONS AND HUMAN PLASMA USING HPLC WITH UV DETECTION
Objective: A simple, Rapid, and sensitive HPLC method utilizing UV detection was developed and validated for the simultaneous estimation of Fluticasone propionate (FP) and Salmeterol xinafoate (SX) in solutions and in vitro human plasma.
Methods: Chromatographic analysis was done on SUPELCO® RP-C18 column (150 x 4.6 mm, 5 μm particle size) with an isocratic mobile phase composed of methanol, acetonitrile, and water (50:20:30, v/v) mixture while flow rate was set to 1 ml/min. Detection with UV at maximum absorbance wavelength (ʎmax) values of 236 and 252 for FP and SX, respectively. Spiked plasma samples were liquid-liquid extracted by diethyl ether and reconstituted using methanol.
Results: Method was accurate and precise over a linear (R2>0.995) range of (0.067-100 µg/ml) and (0.0333-50 µg/ml) for FP and SX, respectively. LOD/lOQ values were 0.13/0.6 and 0.06/0.3 µg/ml for FP and SX, respectively.
The developed method was successfully applied for the analysis of FP and SX in spiked human plasma samples. The method is considered to be accurate and precise over a linear (R2>0.9969) range of (6.67-66.67 µg/ml) and (3.33-33.3 µg/ml) for FP and SX, respectively. Extraction efficiency was approved by recovery values of (94.98–102.46 %) and (96.54–102.62 %) for FP and SX, respectively.
Conclusion: This validated method revealed simple and cheap extraction procedures and detectors, non-buffered mobile phase, and short retention times with excellent resolution
Optimal sizing design and operation of electrical and thermal energy storage systems in smart buildings
Photovoltaic (PV) systems in residential buildings require energy storage to enhance their productivity; however, in present technology, battery storage systems (BSSs) are not the most cost-effective solutions. Comparatively, thermal storage systems (TSSs) can provide opportunities to enhance PV self-consumption while reducing life cycle costs. This paper proposes a new framework for optimal sizing design and real-time operation of energy storage systems in a residential building equipped with a PV system, heat pump (HP), thermal and electrical energy storage systems. For simultaneous optimal sizing of BSS and TSS, a particle swarm optimization (PSO) algorithm is applied to minimize daily electricity and life cycle costs of the smart building. A model predictive controller is then developed to manage energy flow of storage systems to minimize electricity costs for end-users. The main objective of the controller is to optimally control HP operation and battery charge/discharge actions based on a demand response program. The controller regulates the flow of water in the storage tank to meet designated thermal energy requirements by controlling HP operation. Furthermore, the power flow of battery is controlled to supply all loads during peak-load hours to minimize electricity costs. The results of this paper demonstrate to rooftop PV system owners that investment in combined TSS and BSS can be more profitable as this system can minimize life cycle costs. The proposed methods for optimal sizing and operation of electrical and thermal storage system can reduce the annual electricity cost by more than 80% with over 42% reduction in the life cycle cost. Simulation and experimental results are presented to validate the effectiveness of the proposed framework and controller
Improved flat mobile core network architecture for 5G mobile communication systems
The current mobile network core is built based on a centralized architecture, including the S-GW and P-GW entities to serve as mobility anchors. Nevertheless, this architecture causes non-optimal routing and latency for control messages. In contrast, the fifth generation (5G) network will redesign the network service architecture to improve changeover management and deliver clients a better Quality-of-Experience (QoE). To enhance the design of the existing network, a distributed 5G core architecture is introduced in this study. The control and data planes are distinct, and the core network also combines IP functionality anchored in a multi-session gateway design. We also suggest a control node that will fully implement the control plane and result in a flat network design. Its architecture, therefore, improves data delivery, mobility, and attachment speed. The performance of the proposed architecture is validated by improved NS3 simulation to run several simulations, including attachment and inter- and intra-handover. According to experimental data, the suggested network is superior in terms of initial attachment, network delay, and changeover management
A Comprehensive Survey on Resource Allocation for CRAN in 5G and Beyond Networks
The diverse service requirements coming with the
advent of sophisticated applications as well as a large number
of connected devices demand for revolutionary changes in the
traditional distributed radio access network (RAN). To this end,
Cloud-RAN (CRAN) is considered as an important paradigm
to enhance the performance of the upcoming fifth generation
(5G) and beyond wireless networks in terms of capacity, latency,
and connectivity to a large number of devices. Out of several
potential enablers, efficient resource allocation can mitigate various
challenges related to user assignment, power allocation, and
spectrum management in a CRAN, and is the focus of this paper.
Herein, we provide a comprehensive review of resource allocation
schemes in a CRAN along with a detailed optimization taxonomy
on various aspects of resource allocation. More importantly,
we identity and discuss the key elements for efficient resource
allocation and management in CRAN, namely: user assignment,
remote radio heads (RRH) selection, throughput maximization,
spectrum management, network utility, and power allocation.
Furthermore, we present emerging use-cases including heterogeneous
CRAN, millimeter-wave CRAN, virtualized CRAN, Non-
Orthogonal Multiple Access (NoMA)-based CRAN and fullduplex
enabled CRAN to illustrate how their performance can
be enhanced by adopting CRAN technology. We then classify
and discuss objectives and constraints involved in CRAN-based
5G and beyond networks. Moreover, a detailed taxonomy of
optimization methods and solution approaches with different
objectives is presented and discussed. Finally, we conclude the
paper with several open research issues and future directions
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Klippel–Feil Syndrome with Sprengel Deformity and Extensive Upper Extremity Deformity: A Case Report and Literature Review
Introduction: Klippel–Feil syndrome (KFS) is a congenital anomaly resulting from fusion of cervical vertebral bodies secondary to the dysregulation of signaling pathways during somite development. It is commonly associated with scoliosis and Sprengel deformity. We present a case of KFS with commonly associated abnormalities as well as deformities that have not yet been reported in the literature. Case Presentation A 3-year-old girl presented for further evaluation of a left upper extremity deformity following a negative genetic workup. Upon physical exam and radiographic imaging, the patient was diagnosed with KFS and associated abnormalities including cervical scoliosis, Sprengel deformity, and congenital deformity of the left upper extremity. Deformities of the left upper extremity include radioulnar synostosis, a four-rayed hand, and absent thenar musculature. The Sprengel deformity was corrected surgically with a Woodward procedure. Discussion Congenital musculoskeletal deformities can be differentiated based upon spinal and limb embryology. The presence of extraspinal abnormalities not originating from somite differentiation may suggest a severe form of KFS. Important considerations in the workup of the KFS patient include looking for deformities of the shoulder girdle and upper extremities to identify abnormalities for intervention at a young age
Cold-Active Enzymes and Their Potential Industrial Applications—A Review
More than 70% of our planet is covered by extremely cold environments, nourishing a broad diversity of microbial life. Temperature is the most significant parameter that plays a key role in the distribution of microorganisms on our planet. Psychrophilic microorganisms are the most prominent inhabitants of the cold ecosystems, and they possess potential cold-active enzymes with diverse uses in the research and commercial sectors. Psychrophiles are modified to nurture, replicate, and retain their active metabolic activities in low temperatures. Their enzymes possess characteristics of maximal activity at low to adequate temperatures; this feature makes them more appealing and attractive in biotechnology. The high enzymatic activity of psychrozymes at low temperatures implies an important feature for energy saving. These enzymes have proven more advantageous than their mesophilic and thermophilic counterparts. Therefore, it is very important to explore the efficiency and utility of different psychrozymes in food processing, pharmaceuticals, brewing, bioremediation, and molecular biology. In this review, we focused on the properties of cold-active enzymes and their diverse uses in different industries and research areas. This review will provide insight into the areas and characteristics to be improved in cold-active enzymes so that potential and desired enzymes can be made available for commercial purposes
Cold-Active Enzymes and Their Potential Industrial Applications—A Review
More than 70% of our planet is covered by extremely cold environments, nourishing a broad diversity of microbial life. Temperature is the most significant parameter that plays a key role in the distribution of microorganisms on our planet. Psychrophilic microorganisms are the most prominent inhabitants of the cold ecosystems, and they possess potential cold-active enzymes with diverse uses in the research and commercial sectors. Psychrophiles are modified to nurture, replicate, and retain their active metabolic activities in low temperatures. Their enzymes possess characteristics of maximal activity at low to adequate temperatures; this feature makes them more appealing and attractive in biotechnology. The high enzymatic activity of psychrozymes at low temperatures implies an important feature for energy saving. These enzymes have proven more advantageous than their mesophilic and thermophilic counterparts. Therefore, it is very important to explore the efficiency and utility of different psychrozymes in food processing, pharmaceuticals, brewing, bioremediation, and molecular biology. In this review, we focused on the properties of cold-active enzymes and their diverse uses in different industries and research areas. This review will provide insight into the areas and characteristics to be improved in cold-active enzymes so that potential and desired enzymes can be made available for commercial purposes
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