bluuebunny/crossref_metadata_2025_split huggingface dataset:
The CSMA/DM LAN protocol
Authors: Peng Wuxu , Makki Shamila 
Published: January 2006

AbstractWe propose an extension of the classical CSMA/CD protocol that eliminates its three main drawbacks. The new protocol, called dual‐mode CSMA/CD (CSMA/DM), operates in two modes, light mode and heavy mode. The light mode of CSMA/DM is almost the same as the original CSMA/CD protocol and is primarily used when the LAN load is light. The heavy mode is a collision free mode and is applied when the LAN load is heavy.The proposed modification to CSMA/CD is minimal while performance gain is significant. CSMA/DM automatically switches between its two modes based on the observed LAN load. Under heavy mode, the monitor station in a CSMA/DM LAN allocates bandwidth to those busy stations without collisions. The newly added priority scheme in the heavy mode allows stations to reserve bandwidth for their high priority frames.Compared with the current collision‐free fast Ethernet and Gigabit Ethernet, CSMA/DM has the advantage of not needing any extra switches or hubs while maintaining comparable performance. Its priority scheme provides more flexibility on bandwidth distribution than in fast Ethernet and Gigabit Ethernet. It can also be easily adapted for high‐speed wireless LANs. More importantly, CSMA/DM should be a good alternative of the widely used CSMA/CA (collision avoidance) in mobile ad hoc networks (MANET) and sensor networks. Copyright © 2005 John Wiley & Sons, Ltd.
MAC‐assisted topology control forad hocwireless networks
Authors: Rahman A. , Gburzynski P. 
Published: January 2006

AbstractWe considerad hocwireless networks and the topology control problem defined as minimizing the amount of power needed to maintain connectivity. The issue boils down to selecting the optimum transmission power level at each node based on the position information of reachable nodes. Local decisions regarding the transmission power level induce a subgraph of the maximum powered graphGmaxin which edges represent direct reachability at maximum power. We propose a new algorithm for constructing minimum‐energy path‐preserving subgraphs ofGmax, i.e. ones minimizing the energy consumption between node pairs. Our algorithm involves a modification to the medium access control (MAC) layer. Its superiority over previous solutions, up to 60% improvement in sparse networks, demonstrates once again that strict protocol layering in wireless networks tends to be detrimental to performance. Copyright © 2005 John Wiley & Sons, Ltd.
Improved implementation solution and general mobile network architecture for the interworking between MMS and streaming
Authors: Miraj‐E‐Mostafa A. 
Published: January 2006

AbstractThe prospects of multimedia in mobile communication depend largely on effective design of interactive multimedia applications now. Multimedia Messaging Service (MMS) and streaming are two potential multimedia applications for mobile communication. Though MMS has many advantages, a limitation is noted in MMS—an inability to handle a message requiring more space than available in a mobile terminal, as the message must be fully retrieved and stored before its presentation. Moreover, a large message can keep a recipient user waiting long for its retrieval before it is presented, causing poor user‐experience. This paper proposes a new implementation solution for the interworking between MMS and streaming to overcome the limitation. The new solution is consistent with the existing frameworks and working principles of both MMS and streaming. The new solution is compared with the previous solutions, indicating that it has considerable advantages. This paper also presents general network architecture, providing various architectural options, to accommodate the interworking in different situations. The architecture considers many practical cases, like person‐to‐person messaging, messaging involving content providers and multiple network operators, load balancing and scalability in related network servers, operational agreement between a content provider and a network operator, and using existing network infrastructure for the interworking. Copyright © 2005 John Wiley & Sons, Ltd.
Enhancing data throughput and lower correlations quasi orthogonal functions for 3G CDMA systems
Authors: Hou Jia , Lee Moon Ho 
Published: January 2006

AbstractThe forward link of the 3G code‐division multiple‐access (CDMA) system may become limited under the increasing of the number of users. The conventional channelization code, Walsh code, has not enough sizes for much possible users, therefore, the quasi orthogonal function (QOF), which can process optimal cross‐correlation with Walsh code, is considered.To obtain lower correlations and better performance in 3G CDMA system, we investigate a quasi orthogonal function on Jacket matrices in this paper. Secondly, to simplify the detector and improve the bit error rate (BER) performance, we provide a novel detection scheme for QOF CDMA system. Finally, we give a brief discussion about a simple recursive generation of the bent sequences for QOF mask function. Copyright © 2005 John Wiley & Sons, Ltd.
QPSK differential space time coding on different unitary matrices sets and initializations
Authors: Hou Jia , Ho Lee Moon 
Published: January 2006

AbstractThis paper investigates a distinct set of complex unitary matrices for differential space time coding by using QPSK modulation. The numerical results show that the proper selection of the initial transmission matrix and the set of unitary matrices can efficiently improve the bit error rate performance, especially for the antennas correlated fading channel. The computer simulations are evaluated over slow and fast Rayleigh fading channels. Copyright © 2005 John Wiley & Sons, Ltd.
A zone co‐operation approach for efficient caching in mobilead hocnetworks
Authors: Chand Narottam , Joshi R. C. , Misra Manoj 
Published: January 2006

AbstractMobileAd hocNETwork (MANET) presents a constrained communication environment due to fundamental limitations of client resources, insufficient wireless bandwidth and users' frequent mobility. Caching of frequently accessed data in such environment is a potential technique that can improve the data access performance and availability. Co‐operative caching, which allows the sharing and co‐ordination of cached data among clients, can further explore the potential of the caching techniques. In this paper, we propose a novel scheme, calledzone co‐operative(ZC) for caching in MANETs. In ZC scheme, one‐hop neighbours of a mobile client form a co‐operative cache zone. For a data miss in the local cache, each client first searches the data in its zone before forwarding the request to the next client that lies along routing path towards server. As a part of cache management, cache admission control andvalue‐based replacement policy are developed to improve the data accessibility and reduce the local cache miss ratio. An analytical study of ZC based on data popularity, node density and transmission range is also performed. Simulation experiments show that the ZC caching mechanism achieves significant improvements in cache hit ratio and average query latency in comparison with other caching strategies. Copyright © 2006 John Wiley & Sons, Ltd.
Improving broadcast performance by traffic isolation in wirelessad hocnetworks
Authors: Purtoosi Reza , Taheri Hassan , Mohammadi Abbas , Foroozan Foroohar 
Published: January 2006

AbstractIn this paper we propose a new broadcasting algorithm. In the proposed method we significantly reduce the broadcast overhead and also improve the broadcast delivery ratio in mobile networks. A novel traffic isolation method has been used which reduces the control message exchange. The proposed broadcasting method is based on a clustering method called ‘stability‐based clustering algorithm’ which had been proposed before. The broadcasting traffic is divided into internal (flow inside a cluster) and external traffic (flow among the clusters). For internal flooding traffic, cluster‐heads and gateways are responsible for re‐broadcasting but for external type, border nodes may perform the forwarding function as well. This simplifies the gateway selection method through the local selection of gateway nodes by its cluster head. Therefore, a cluster head selects gateway in its own cluster without any knowledge of other clusters. Considering the effect of mobility and node density, simulations have been conducted in a number of wireless environments. Simulation results show the broadcast coverage is close to 100% at different node speeds. Moreover, we study the broadcast parameters in light and dense networks and show improvement of the overhead and the number of forward nodes in comparison to other broadcasting methods. Copyright © 2005 John Wiley & Sons, Ltd.
The evolving UK wind energy industry: critical policy and management aspects of the emerging research agenda
Authors: Strachan Peter A. , Lal David , von Malmborg Fredrik 
Published: January 2006

AbstractIn recent years, renewable energy – and in particular wind power – has come to the fore of both international and UK national environmental policy debates. In addition to helping to meet its Kyoto obligations, the British Government has indicated its desire for a much larger slice of the international wind energy market, and has consequently developed a national strategy to stimulate a more vibrant UK wind energy industry. With this in mind, the British Government's Climate Change Programme (DETR, 2000) and more recent Energy White Paper (DTI, 2003) outline the UK energy strategy for the coming two decades, with wind power featuring as a core component. This article critically considers the prospects for the development of a wind energy industry in the UK and introduces five strategic opportunities and five strategic barriers in this evolving segment of the energy market. The article concludes with recommendations to enhance public acceptance of wind energy and four important areas for future research are outlined. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
Public and stakeholder participation in European water policy: a critical review of project evaluation processes
Authors: Videira Nuno , Antunes Paula , Santos Rui , Lobo Gonçalo 
Published: January 2006

AbstractThe recent reform of the European water policy recognizes the importance of developing effective mechanisms to support public and stakeholder participation in river basin decision‐making processes. This paper critically reviews the evaluation processes of different types of water related project in five European countries (Portugal, Greece, The Netherlands, the United Kingdom and Spain), with respect to participatory criteria. The horizontal comparison of these cases accounted for criteria such as the political and institutional context, the design, the implementation and the evaluation of the outcomes of participation. The results indicated that, in the majority of the case studies, participation was simply adopted to conform to the requisites of the Environmental Impact Assessment Directive. Thus, there was truly no room for the active involvement and collaboration of the interested parties. The development of guidelines, drawing from the analysis of past experiences, is expected to support the implementation of the participatory objectives of the EU water policy. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
Policy profile: how Dutch environmental policy contributes to meet European environmental standards; Dutch environmental balance
Authors: van Wezel Annemarie P. , Kruitwagen Sonja , Maas Rob 
Published: January 2006

AbstractIn the Dutch ‘environmental balance’ the effectiveness of Dutch environmental policy in meeting European environmental standards is evaluated. Major themes in the environmental balance are eco‐efficiency, climate change, manure policy, air quality and urban environment, and the general developments in Dutch environmental policy in the past 15 years. Main conclusions are that European policy results in a considerable emission reduction, however not enough to meet EU environmental quality standards. Compared to other EU member states, The Netherlands is densely populated and built, resulting in high emissions per square kilometre. Moreover, The Netherlands has a substantial contribution of contamination from abroad, although it is itself a net exporter of pollution. Therefore, additional national measures are necessary to meet the EU quality standards. The wish to have a ‘level playing field’ for industry may conflict with the wish to protect citizens equally against a low environmental quality. Spatial solutions are frequently chosen as additional measures, by separating sources of pollution from citizens or nature. In this way, additional national emission reduction measures on top of European emission policy are avoided. However, this spatial separation is not always effective. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
The role of indicators in improving timeliness of international environmental reports
Authors: Rosenström Ulla , Lyytimäki Jari 
Published: January 2006

AbstractEnvironmental indicators were developed mainly to improve information flows from scientists to policy‐makers. This article discusses the importance of timely environmental data and investigates the influence of indicator‐based reporting on the data timeliness of environmental reports by international organizations. Timeliness of information contributes to the quality and appeal of the reports, and to their role as early warning tools, and increases their usability by decision‐makers in short‐term decision cycles. The results of an analysis of 11 international reports by the European Environmental Agency (EEA) and the Organization for Economic Co‐Operation and Development (OECD) show a considerable time lag of three years on average, with only minor development towards more timely reporting. The results suggest that the introduction of environmental indicators has not improved the timeliness of reporting. In order to overcome these problems, the article recommends some methods for improving timeliness. These include better choice of indicators in smaller sets, use of preliminary data and outlooks, development of new indicators, publishing on the internet and more effective use of internet databases to avoid intermediate levels in data collection. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
Another Example of the Instability of a Keggin‐Type Heteropolyanion in the Presence of Aqueous Hydrogen Peroxide: From [AsW12O40]3– to Low‐Nuclearity Oxoperoxotungstates – Crystal Structure of [(nHex)4N]3[AsO4{W2O2(μ‐O2)2(O2)2}2]
Authors: Piquemal Jean‐Yves , Salles Laurent , Chottard Geneviève , Herson Patrick , Ahcine Chehrazed , Brégeault Jean‐Marie 
Published: January 2006

AbstractThe Keggin dodecatungstoarsenato anion of HNa2[AsW12O40] is inherently unstable in aqueous hydrogen peroxide and is mainly degraded to [AsO4{W2O2(μ‐O2)2(O2)2}2]3–, [HAsO4{W2O2(μ‐O2)2(O2)2}]2– and [{WO(O2)2(H2O)}2(μ‐O)]2–. These anions were isolated as salts and identified by elemental and spectroscopic analyses. The salt with the formula [(nC6H13)4]3[AsO4{W2O2(μ‐O2)2(O2)2}2] was obtained from the reaction of tungstic acid, “H2WO4” (or HNa2[AsW12O40]·nH2O), with aqueous hydrogen peroxide, HNa2[AsO4]·7H2O and [(nC6H13)4N]Cl. The structure was refined with R1 = 0.058 and wR2 = 0.067 [monoclinic C2 (no. 5); a = 20.516(6) Å, b = 15.923(4) Å, c = 14.902(2) Å, β = 91.64(1)°, Z = 2]. The vibrational spectra (IR and Raman) suggest that the overall structure is maintained in organic solvents. The close relation between the phosphate‐ and arsenate‐based complexes indicates that fluxional behaviour may exist for all these di‐ and tetranuclear complexes. Fluxionality may play a key role in the transfer of active oxygen (from peroxo groups) to organic substrates via {WO(O2)2} units. It is shown that the heteroligand [XOp]n– (X = As, HAs, MeAs, P, HP, etc.) has a marked effect on the stoichiometric and regioselective epoxidation of (R)‐(+)‐limonene to 1,2‐epoxide at ambient temperature, for a given pH of the aqueous phase. The oxodiperoxo complexes can be used to carry out epoxidation stoichiometrically and regioselectively with (R)‐(+)‐limonene, but can also be employed in a catalytic process in a two‐phase mixture at room temperature. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Study on separation of aristolochic acid I and II by micellar electrokinetic capillary chromatography and competition mechanism between SDS and β‐cyclodextrin
Authors: Li Wei , Chen Zheng , Liao Yiping , Liu Huwei 
Published: January 2006

AbstractIn this study, a rapid MEKC method using 40 mM sodium borate buffer containing 50 mM SDS as surfactant was developed for the analysis of aristolochic acid (AA) in Aristolochia plants. Baseline separation of AA‐I and AA‐II was achieved within 3 min with high separation efficiency, satisfactory sensitivity, repeatability, and recovery. Resolution between AA‐I and AA‐II is above 5 and great performance with higher than 200 000 theoretical plate numbers was obtained. The detection limits (based on 3 S/N) were both 1.0 μg/mL. Two kinds of AA in 35 herbal samples of Aristolochia plants were successfully determined. The competition mechanism between β‐CD and SDS was also investigated by changing the content ratio of β‐CD and SDS.
Determination of biogenic amines in HeLa cell lysate by 6‐oxy‐(N‐succinimidyl acetate)‐9‐(2'–methoxycarbonyl) fluorescein and micellar electrokinetic capillary chromatography with laser‐induced fluorescence detection
Authors: Cao Liwei , Wang Hong , Ma Ming , Zhang Huashan 
Published: January 2006

AbstractAn MEKC‐LIF method using 6‐oxy‐(N‐succinimidyl acetate)‐9‐(2'‐methoxy‐carbonyl) fluorescein (SAMF) newly synthesized in our lab as a labeling reagent for the separation and determination of eight typical biogenic amines was proposed. After careful study of the derivatization condition such as pH value, reagent concentration, temperature, and reaction time, derivatization reaction was accomplished as quickly as 10 min with stable yield. Optimal separation of SAMF‐labeled amines was achieved with a running buffer (pH 9.3) containing 30 mM boric acid, 25 mM SDS, and 20% v/v ACN. The proposed method allowed biogenic amines to be determined with LODs as low as 0.25–2.5 nmol/L and RSD values from 0.4 to 4.5%. The present method has been successfully used to monitor biogenic amines in HeLa cells and fish samples. This study exploits the potential of MEKC‐LIF with SAMF labeling as a tool for monitoring biogenic amines involved in complex physiological and behavioral processes in various matrices.
Separation and quantitation of the four stereoisomers of itraconazole in pharmaceutical formulations by electrokinetic chromatography
Authors: Castro‐Puyana María , Crego Antonio L. , Marina M. Luisa 
Published: January 2006

AbstractThe four stereoisomers of itraconazole were resolved for the first time by EKC using a CD as chiral selector. A study on the enantiomeric separation ability of different neutral CDs was carried out. Heptakis‐2,3,6‐tri‐O‐methyl‐β‐CD was shown to provide the highest values for the enantiomeric resolution. The influence of some experimental conditions, such as pH, chiral selector concentration, and temperature, on the enantiomeric separation was also studied. The use of a 100 mM phosphate buffer (pH 2.5), 30 mM in heptakis‐2,3,6‐tri‐O‐methyl‐β‐CD together with an applied voltage of 30 kV and a temperature of 20°C enabled the separation of the enantiomers of itraconazole with high resolutions (Rs > 3.0). Finally, the method was validated and successfully applied to the quantitation of itraconazole in three pharmaceutical formulations.
Capillary electrochromatography of biologically relevant flavonoids
Authors: Stöggl Wolfgang M. , Huck Christian W. , Stecher Günther , Bonn Günther K. 
Published: January 2006

AbstractFlavonoids were separated utilizing CEC technique. Baseline separation of biologically relevant flavonoids was obtained using a 100 μm ID fused‐silica capillary filled with 3 μm Silica‐C18 material and an optimized mobile phase comprising of 20 mM Tris‐HCl (pH 6.5), ACN and water at a ratio of 10/40/50 v/v/v. Separations were carried out at 25 kV and a column temperature of 25°C. The influence of relevant parameters for the CEC separation, such as buffer concentration, pH, separation voltage, and ACN concentration, was investigated and optimized. Dependencies of the electroendoosmotic flow (EOF) on these parameters and effects on the resolution of the analytes were studied. During analyses the solvents used for dissolving the samples turned out to have significant effects on the separation of flavonoids. The optimized system was then successfully used for the separation of the flavonoids epicatechin, myricetin, quercetin, naringenin, and hesperetin. CEC turned out to be a useful complementary tool for the economic analysis of flavonoids in addition to common HPLC, μHPLC, and CE methodologies. This method can be used for real applications in phytomics.
Rapid determination of acyclovir in plasma and cerebrospinal fluid by micellar electrokinetic chromatography with direct sample injection and its clinical application
Authors: Yeh Hsin‐Hua , Yang Yuan‐Han , Chen Su‐Hwei 
Published: January 2006

AbstractA simple MEKC with UV detection at 254 nm for analysis of acyclovir in plasma and in cerebrospinal fluid (CSF) by direct injection without any sample pretreatment is described. The separation of acyclovir from biological matrix was performed at 25°C using a BGE consisting of Tris buffer with SDS as the electrolyte solution. Several parameters affecting the separation of the drug from biological matrix were studied, including the pH and concentrations of the Tris buffer and SDS. Using dyphylline as an internal standard, the linear ranges of the method for the determination of acyclovir in plasma and in CSF all exceeded the range of 2–50 μg/mL; the detection limit of the drug in plasma and in CSF (S/N = 3; injection 3.45 kPa, 5 s) was 1.0 μg/mL. The applicability of the proposed method for determination of acyclovir in plasma and CSF collected at 8 h after intravenous administration of 500 mg acyclovir (Zovirax®) in two patients with herpes simplex encephalitis was demonstrated.
An on‐column derivatization method for the determination of the enantiomeric excess of chiral primary amines via indirect enantioseparation by micellar electrokinetic chromatography
Authors: Cheng Jiayi , Kang Jingwu 
Published: January 2006

AbstractA method used for determining the enantiomeric excess (ee) value of chiral amino compounds by MEKC is described. In this method, the plug‐plug type electrophoretic medicated microanalysis technique was employed to convert the enantiomers of chiral amino compounds into their diastereomers through an on‐column derivatization with o‐phthaldialdehyde and the chiral reagent N‐acetyl‐L‐cysteine. Afterwards, the resulting diastereomers were easily separated with a nonchiral MEKC approach. The on‐column derivatization conditions and the separation conditions were optimized and the method was validated with five chiral amino compounds. The present method can be used for assaying the ee value of chiral amino compound with various structural features, especially for those that have no UV chromophore. Therefore, the method can be potentially used for screening or evaluation of the asymmetric catalysts developed by the combinatorial chemistry. In this case, the ee values of chiral products with various structures need to be measured; however, this is difficult for direct chiral separation approach due to the fact that the chiral selectivity is strongly dependent on the structure of the analytes. The method is simple, reliable, and automatic.