Exclusive Usage Research Articles

Power and Subcarrier Allocation for Multicast Service in OFDMA Decode-and-Forward Relay Systems

Orthogonal Frequency Division Multiplexing Access (OFDMA) relay system is a promising technique for increasing the capacity and the range of wireless communication systems. Dynamic resource allocation for OFDMA relay systems plays an important role in improving the system performance. However, most of the resource allocation algorithms are designed for the unicast traffics, and resource allocation algorithm for multicast traffics in OFDMA relay systems has received little attention. In this paper, the resource allocation problem for the decode-and-forward relay assisted OFDMA multicast system is considered. Our goal is to maximize the sum rate of the multicast system under the constraints of total power limit and exclusive subcarrier usage. The multicast resource allocation problem is formulated as a mixed integer programming problem. The problem is firstly solved by using Lagrangian dual decomposition method, resulting in an asymptotically optimal joint subcarrier and power allocation algorithm with computational complexity being linear with the number of multicast groups and subcarriers. Furthermore, a low complexity suboptimal resource allocation algorithm is presented to further reduce the computational complexity. Simulation results show that both the proposed optimal and suboptimal algorithms can significantly improve the system performance and the proposed suboptimal algorithm can achieve a near optimal solution.

BAF60 A, B, and Cs of muscle determination and renewal

Developmental biologists have defined many of the diffusible and transcription factors that control muscle differentiation, yet we still have only rudimentary knowledge of the mechanisms that dictate whether a myogenic progenitor cell forms muscle versus alternate lineages, including those that can be pathological in a state of disease or degeneration. Clues about the molecular basis for lineage determination in muscle progenitors are only now emerging from studies of chromatin modifications that avail myogenic genes for transcription, together with analysis of the composition and activities of the chromatin-modifying complexes themselves. Here we review recent progress on muscle determination and explore a unifying theme that environmental cues from the stem or progenitor niche control the selection of specific subunit variants of the switch/sucrose nonfermentable (SWI/SNF) chromatin-modifying complex, creating a combinatorial code that dictates whether cells adopt myogenic versus nonmyogenic cell fates. A key component of the code appears to be the mutually exclusive usage of the a, b, and c variants of the 60-kD structural subunit BAF60 (BRG1/BRM-associated factor 60), of which BAF60c is essential to activate both skeletal and cardiac muscle programs. Since chromatin remodeling governs myogenic fate, the combinatorial assembly of the SWI/SNF complex might be targeted to develop drugs aimed at the therapeutic reduction of compensatory fibrosis and fatty deposition in chronic muscular disorders.

Envelope diversity, characteristics of V3 region and predicted co-receptor usage of human immunodeficiency viruses infecting north indians

Subtypes of human immunodeficiency virus type 1 circulating in 21 north Indian patients were characterized based on the partial sequence of the gp120 envelope protein. A majority of viruses (85.7%, 18/21) were subtype C, while 14.3% (3/21) were subtype A. Sequence analysis revealed that the V3 region was highly conserved compared with V4 and V5. The predicted use of co-receptors indicated exclusive usage of R5, except for two subtype A viruses (AIIMS279 and AIIMS281). Our results demonstrate conservation within the V3 loop of subtype C viruses, and suggest the emergence of non-clade C viruses in the north Indian population.

A robust AHP-DEA method for measuring the relative efficiency: An application of airport industry

Article history: Received July 16, 2011 Received in Revised form September, 3, 2011 Accepted 18 September 2011 Available online 29 September 2011 Measuring the relative efficiency of similar units has been an important topic of research among many researchers. Data envelopment analysis has been one of the most important techniques for measuring the efficiency of different units. However, there are some limitations on using such technique and some people prefer to use other methods such as analytical hierarchy process to measure the relative efficiencies. Besides, uncertainty in the input data is another issue, which makes some misleading results. In this paper, we present an integrated robust DEA-AHP to measure the relative efficiency of similar units. The proposed model of this is believed to capable of presenting better results in terms of efficiency compared with exclusive usage of DEA or AHP. The implementation of the proposed model is demonstrated for a real-world case study of Airport industry and the results are analyzed.

TOFU: Semi-Truthful Online Frequency Allocation Mechanism for Wireless Networks

In wireless networks, we need to allocate spectrum efficiently. One challenge is that the spectrum usage requests often come in an online fashion. The second challenge is that the secondary users in a cognitive radio network are often selfish and prefer to maximize their own benefits. In this paper, we address these two challenges by proposing TOFU, a semi-truthful online frequency allocation method for wireless networks when primary users can sublease the spectrums to secondary users. In our protocol, secondary users are required to submit the spectrum bid α time slots before its usage. Upon receiving an online spectrum request, our protocol will decide whether to grant its exclusive usage or not, within at least γ time slots of requests' arrival. We assume that existing spectrum usage can be preempted with some compensation. For various possible known information, we analytically prove that the competitive ratios of our methods are within small constant factors of the optimum online method. Furthermore, in our mechanisms, no selfish users will gain benefits by bidding lower than their willing payment. Our extensive simulation results show that they perform almost optimum: Our methods get a total profit that is more than 95% of the offline optimum when γ is about the duration of spectrum usage Δ.

Efficient and Strategyproof Spectrum Allocations in Multichannel Wireless Networks

In this paper, we study the spectrum assignment problem for wireless access networks. We assume that each secondary user will bid a certain value for exclusive usage of some spectrum channels for a certain time period or for a certain time duration. A secondary user may also require the exclusive usage of a subset of channels, or require the exclusive usage of a certain number of channels. Thus, several versions of problems are formulated under various different assumptions. For the majority of problems, we design PTAS or efficient constant-approximation algorithms such that overall profit is maximized. Here, the profit is defined as the total bids of all satisfied secondary users. As a side product of our algorithms, we are able to show that a previously studied Scheduling Split Interval Problem (SSIP), in which each job is composed of t intervals, cannot be approximated within O(t1-∈) for any small ∈ >; 0 unless NP = ZPP. Opportunistic spectrum usage, although a promising technology, could suffer from the selfish behavior of secondary users. In order to improve opportunistic spectrum usage, we then propose to combine the game theory with wireless modeling. We show how to design a truthful mechanism based on all of these algorithms such that the best strategy of each secondary user to maximize its own profit is to truthfully report its actual bid.

Introduction to the Issue on Cooperative Communication and Signal Processing in Cognitive Radio Systems

Dynamic spectrum access brings an emerging paradigm shift in improving spectrum utilization significantly from the conventional exclusive allocation and usage of spectrum resource. It allows secondary unlicensed users to dynamically share the spectrum with primary licensed users without affecting the normal spectrum utilization in the primary systems. Cognitive radio (CR) has become an important technology to promote dynamic spectrum access by opportunistically sensing and exploiting the spectrum holes. Meanwhile cooperative relay technology brings another paradigm shift in wireless communication and signal processing by introducing cooperative diversity through distributed transmission and processing with user and node collaboration. In the context of cognitive radio systems, cooperative communication is inspiring new design concepts and bringing new dimensions to dramatically improve the spectrum utilization and efficiency in wireless networks.

Genetic architecture of HIV-1 genes circulating in north India & their functional implications

This review presents data on genetic and functional analysis of some of the HIV-1 genes derived from HIV-1 infected individuals from north India (Delhi, Punjab and Chandigarh). We found evidence of novel B/C recombinants in HIV-1 LTR region showing relatedness to China/Mynmar with 3 copies of Nfκb sites; B/C/D mosaic genomes for HIV-1 Vpr and novel B/C Tat. We reported appearance of a complex recombinant form CRF_02AG of HIV-1 envelope sequences which is predominantly found in Central/Western Africa. Also one Indian HIV-1 envelope subtype C sequence suggested exclusive CXCR4 co-receptor usage. This extensive recombination, which is observed in about 10 per cent HIV-1 infected individuals in the Vpr genes, resulted in remarkably altered functions when compared with prototype subtype B Vpr. The Vpu C was found to be more potent in causing apoptosis when compared with Vpu B when analyzed for subG1 DNA content. The functional implications of these changes as well as in other genes of HIV-1 are discussed in detail with possible implications for subtype-specific pathogenesis highlighted.

Making Tablets or Taking Tablets?ṭuppa/u ṣabātuin Assyria

Middle Assyrian texts have a phraseṭuppa ṣab¯atu, which is usually understood to mean “to take (possession of) a tablet”. There is a corresponding type of tablet called aṭuppu ṣabittu(plural (ṭuppatu ṣabbutātu). This article contends thatṭuppa ṣabātuis a technical term for drawing up a formal document, and thatṭuppu ṣabittuis a “formally drawn-up tablet”, normally if not invariably involving at least one seal impression, used both in private commercial contexts and in public administration. It is further maintained that this usage survives into Neo-Assyrian times, when its most frequent (but not exclusive) usage is at the end of a legal document where a witness (often identified as a scribe) is described asṣābit ṭuppi: this has been understood to mean that this scribe retained possession of the document, or that a third party “kept” the document. In the light of the fresh Middle Assyrian evidence, it is preferable to see it as referring to the scribe “who drew up the document”.

SALSA: Strategyproof Online Spectrum Admissions for Wireless Networks

It is imperative to design efficient and effective online spectrum allocation methods since requests for spectrums often come in an online fashion. In this paper, we propose SALSA, strategyproof online spectrum admission for wireless networks. We assume that the requests arrival follows the Poisson distribution. Upon receiving an online spectrum request, our protocol will decide immediately whether to grant its exclusive usage or not, and how much the request should pay. Preempting existing spectrum usage is not allowed. We proposed two protocols that have guaranteed performances for two different scenarios: 1) random-arrival case: the bid values and requested time durations follow some distributions that can be learned, or 2) semi-arbitrary-arrival case: the bid values could be arbitrary, but the request arrival sequence is random. We analytically prove that our protocols are strategyproof, and are both approximately social efficient and revenue efficient. Our extensive simulation results show that they perform almost optimum. Our method for semi-arbitrary-arrival model achieves social efficiency and revenue efficiency almost 20-30 percent of the optimum, while it has been proven that no mechanism can achieve social efficiency ratio better than 1/e \simeq 37 \rm percent. Our protocol for the random-arrival case even achieves social efficiency and revenue efficiency two-six times the expected performances by the celebrated VCG mechanism.

Simulation of Exclusive Truck Facilities on Urban Freeways

This paper assesses the impact of exclusive truck facilities on urban freeway performance. A large-scale regional microscopic traffic simulation model is developed for morning and afternoon peak hours and is used to model two alternative truckway configurations in the Greater Toronto Area, including a truck-only highway and a truck lane conversion on Highway 401. Demand inputs to the microsimulation model are generated by a regional transportation demand model that provides origin-destination matrices for light, medium, and heavy trucks and passenger cars. Plug-ins are developed to represent a truck-only lane in the simulation environment. The simulation model is successfully calibrated to reflect observed road counts and to produce realistic congestion patterns. The effect of infrastructure changes on travel distances, travel times, exclusive truck lane usage, and travel speeds is assessed. Microscopic simulation allows queuing formation/dissipation and bottlenecks to be represented and allows for separate analysis of truck and car performance. Addition of a 4-lane truck-only highway results in greater travel time improvements for trucks, and it sometimes results in shifting of traffic bottlenecks on Highway 401 to downstream locations. Conversion of a freeway lane on Highway 401 results in increased congestion for passenger cars, but improved travel speeds for trucks. Both scenarios show truck facility usage ranges from 100 to 800 trucks per hour per direction.

Does Cognitive Radio Need Policy Innovation?

This contribution addresses the impact of cognitive radio on the regime of radio spectrum governance. To avoid harmful interference the current paradigm of spectrum governance uses the principle of separation. Thereby each application and user or user group is being assigned a specific part of the spectrum for a specific location. Cognitive radio defies this principle because cognitive radios monitor the spectrum and select an unused part for their transmission. This capability provides a new solution in addressing the issue of spectrum scarcity. However, its dynamic operating principle to access spectrum runs counter to the prevailing static spectrum management method. The focus of this contribution is on the implications of dynamic spectrum access for national and international spectrum policy in the light of the current practice of assignments based on (exclusive) usage rights and prescribed applications.

Shared or exclusive radio waves? A dilemma gone astray

Ever increasing demand for commercial wireless applications has forced a rethink of radio wave coordination arrangements. Attempts to reform prescriptive centralised approaches have targeted a model of exclusive usage rights through ownership and markets, and a regime of shared usage through free access and collaborative platforms. Both have been quite successful. However, the diametrically opposed ideological nature of these two alternatives has also polarised the reform movement. Multidisciplinary approaches and the purely conceptual nature of existing policy research have only exacerbated these differences. I argue here that this policy dilemma has erred. At a conceptual level, the focus on two reform regimes mischaracterises the true set of policy choices. At a practical level, the emphasis on extreme views of these two regimes is an inaccurate depiction of actual policy reforms. Furthermore, the implied incompatibility between the two reform regimes belies their complementary nature.

Optimization of the HA-1-Specific T Cell Receptor for Gene Therapy of Hematological Malignancies.

Abstract 4093Poster Board III-1028Relapsed hematological malignancies after HLA-matched allogeneic stem cell transplantation (allo-SCT) are treated by donor lymphocyte infusion (DLI), inducing long-lasting complete remissions. However, treatment of relapsed hematological malignancies after allo-SCT with DLI is associated with induction of graft versus host disease (GvHD). It has been demonstrated that T cells recognizing minor histocompatibility antigens (mHags) selectively expressed on hematopoietic cells mediate anti-leukemic reactivity after allo-SCT without causing GvHD. mHags are derived from genetically polymorphic proteins that can be differentially expressed between donor and recipient. The mHag HA-1 is presented in the context of HLA-A2. The HA-1 tissue distribution is restricted to hematopoietic cells and carcinomas, making it an attractive target antigen to treat hematological malignancies relapsing after allo-SCT when the patient is HA-1+ and the donor is HA-1-. Therefore, adoptive transfer of HA-1-TCR gene modified T cells might be an attractive strategy to separate GvHD from graft versus leukemia effect (GvL). For optimal anti-leukemic reactivity, high expression of introduced TCRs and persistence of the gene modified T cells is important. Based on the previously reported low HA-1-TCR expression on HA-1-TCR modified T cells, optimization of the strategy is required. Several strategies to improve expression of the introduced TCR have been described. Protein expression of the TCR chains can be enhanced by codon optimization. In addition, preferential pairing facilitated by introduction of an extra disulfide bond in the constant regions of the TCR chains can increase the cell surface expression of the transferred TCR. Another strategy based on the fact that TCRs differ in their capacity to compete for cell surface expression, is to select recipient T cells with weak competitor phenotypes. In this study, we investigated the cause of low HA-1-TCR expression after gene transfer, and used the different strategies to increase HA-1-TCR expresssion. To study whether low HA-1-TCR expression was due to inefficiency of the TCRα and β chains to pair, TCR-deficient jurkat cells were transduced with the individual TCRα and TCRβ chains in combination with 17 different TCRα chains and TCRβ chains. Results indicated that low HA-1-TCR expression was not due to inefficient pairing of the HA-1-TCR chains, but caused by low HA-1-TCRβ chain expression on the cell surface. To investigate whether low cell surface expression of the HA-1-BV6S4 chain was due to intrinsic properties, the CDR1 and CDR3 region of the HA-1-TCR BV6S4 chain were exchanged with the CDR1 and CDR3 region of the HA-2-TCRβ (BV6S2) chain. We demonstrated that exchange of the HA-1-TCRβ CDR1 region with the HA-2-TCRβ CDR1 region resulted in improved TCR-expression, however, the HA-1-specificity was completely abolished, indicating that the HA-1-TCRβ CDR1 region is crucial for HA-1-specificity. Furthermore, since there is exclusive TCRBV6S4 chain usage of HA-1-specific T cells, we were unable to select for another HA-1-TCR for clinical use, and were pressed to optimize the HA-1-TCRβ chain. Both codon optimization of the HA-1-TCR chains aiming at improving protein expression and inclusion of cysteine residues in the HA-1-TCR chains aiming at inducing preferential pairing resulted in a significant increase in HA-1-TCR expression. Combining the two strategies increased the HA-1-TCR expression even more, resulting in 70% and 35% of tetramer positive HA-1-TCR transferred weak competitor and strong competitor T cells, respectively. In addition, the HA-1-TCR engineered T cells were able to efficiently recognize target cells that endogenously process and present HA-1, independent of whether the recipient T cells were strong or weak competitor T cells. These results illustrate that engineering of the HA-1-TCR by codon optimization and introduction of an extra cysteine bond resulted in high numbers of high-avidity HA-1-TCR in any T cell of choice irrespective of the properties of the endogenous TCR. Disclosures:No relevant conflicts of interest to declare.

Evolution of SIV toward RANTES resistance in macaques rapidly progressing to AIDS upon coinfection with HHV-6A

Progression to AIDS is often associated with the evolution of HIV-1 toward increased virulence and/or pathogenicity. Evidence suggests that a virulence factor for HIV-1 is resistance to CCR5-binding chemokines, most notably RANTES, which are believed to play a role in HIV-1 control in vivo. HIV-1 can achieve RANTES resistance either by phenotypic switching from an exclusive CCR5 usage to an expanded coreceptor specificity, or by the acquisition of alternative modalities of CCR5 usage. An infectious agent that might promote the evolution of HIV-1 toward RANTES resistance is human herpesvirus 6A (HHV-6A), which is frequently reactivated in HIV-1-infected patients and is a potent RANTES inducer in lymphoid tissue. SIV isolates obtained from pig-tailed macaques (M. nemestrina) after approximately one year of single infection with SIV(smE660) or dual infection with SIV(smE660) and HHV-6A(GS) were characterized for their growth capacity and sensitivity to HHV-6A- and RANTES-mediated inhibition in human or macaque lymphoid tissues ex vivo. Four out of 4 HHV-6A-coinfected macaques, all of which progressed to full-blown AIDS within 2 years of infection, were found to harbor SIV variants with a reduced sensitivity to both HHV-6A and RANTES, despite maintaining an exclusive CCR5 coreceptor specificity; viruses derived from two of these animals replicated even more vigorously in the presence of exogenous HHV-6A or RANTES. The SIV variants that emerged in HHV-6A-coinfected macaques showed an overall reduced ex vivo replication capacity that was partially reversed upon addition of exogenous RANTES, associated with suppressed IL-2 and enhanced IFN-gamma production. In contrast, SIV isolates obtained from two singly-infected macaques, none of which progressed to AIDS, maintained HHV-6A/RANTES sensitivity, whereas the only AIDS progressor among singly-infected macaques developed an SIV variant with partial HHV-6A/RANTES resistance and increased replication capacity, associated with expanded coreceptor usage. These results provide in vivo evidence of SIV evolution toward RANTES resistance in macaques rapidly progressing to AIDS. RANTES resistance may represent a common virulence factor allowing primate immunodeficiency retroviruses to evade a critical mechanism of host antiviral defense.

Differences in molecular evolution between switch (R5 to R5X4/X4-tropic) and non-switch (R5-tropic only) HIV-1 populations during infection

The recent introduction of entry inhibitors in the clinic as components of antiretroviral treatment has heightened the interest in coreceptor use of human immunodeficiency virus type 1 (HIV-1). Viruses using CCR5 as coreceptor (R5 viruses) are generally present over the entire course of infection whereas viruses using the CXCR4 coreceptor (R5X4/X4 viruses) emerge in about 50% of infected individuals during later stages of infection. The CCR5-to-CXCR4 switch represents a concern because CCR5 inhibitors, while suppressing R5 viruses, may allow the emergence of CXCR4-tropic viruses. In this study, HIV-1 populations that maintained CCR5 usage during infection were compared with populations that switched coreceptor usage to include CXCR4 later during infection, with the aim to find molecular properties of the virus populations associated with the CCR5-to-CXCR4 switch. We amplified and molecularly cloned the V1–V3 region of the HIV-1 envelope from 51 sequential HIV-1 isolates derived from 4 to 10 serial samples for each of the patients. Four of the patients had virus populations that switched coreceptor usage to include CXCR4 (switch populations: SP) during infection and four patients had viral populations that maintained exclusive CCR5 usage (non-switch populations: nSP). Coreceptor usage was determined experimentally on individual clones from dualtropic R5X4 isolates. In nSP we found that the number of potential N-linked glycosylation sites (PNGS) increased over time, whereas no pattern of change was observed in SP. We also found differences in V2 length and V3 charge between R5 viruses of nSP and R5 viruses of SP before the switch. The V2 region was significantly longer in R5 viruses of SP compared to viruses of nSP throughout the course of infection, and the V3 charge increased with time in R5 populations from SP, while it remained unchanged or decreased in nSP. These molecular properties could prove important for understanding the evolution of coreceptor usage in HIV-1 populations, and maybe even for predicting an upcoming coreceptor switch at early stages after primary infection.

Duetting—A mechanism to strengthen pair bonds in a dispersed pair‐living primate (Lepilemur edwardsi)?

Duetting is defined as an interactively organized pair display in which one pair partner coordinates its vocalizations in time with those of the other. It is widespread among tropical birds and cohesive pair-living primates, in which it is suggested to strengthen pair bonds. We know very little about the presence and function of duetting in dispersed pair-living mammals. We studied duetting behavior in a solitary foraging, but pair-sleeping, primate, the Milne Edwards' sportive lemur, in a dry deciduous forest of north-western Madagascar. We radio-tracked six pairs throughout 1 year and recorded their sleeping sites and associations, home-range use, and vocal and behavioral interactions. Three different periods were covered (mating, pregnancy, and offspring care). Sleeping partners form long-term pair bonds, indicated by an almost exclusive pair-specific usage of sleeping sites and home-ranges across periods. We explored three functional hypothesis of duetting: mate reunion, pair reunion, and joint-territorial defense. Pairs regularly engaged in duet calling. Duetting increased significantly during the offspring care period. Duetting occurred significantly more often at feeding sites than at sleeping sites. Pair partners synchronized behavioral activities after duetting. The activity most often synchronized was locomotion. Pair partners played an equal role in duetting with no difference between sexes in starting or terminating duetting. Altogether, our results provide support for the hypothesis that in dispersed pair-living primates, duetting evolved as a mechanism to coordinate activities between pair partners dispersed in space, to strengthen pair bonds, and, perhaps, to limit infanticide and nutritional stress in lactating females.

The Process of the Metric System’s Acceptance in Korea and Its International Context

In July 2007, the Republic of Korea finally pushed forward the exclusive usage of the metric system, prohibiting the customary use of pyeong, the Japanese unit of area, and geun and don, Korean traditional weight units. The Gabo Reform (1894) was the first overall reform of the metrology system, and in 1902, the metric system was introduced in Korea, adjusting the traditional base units of cheok, seung, and nyang to meter-based scales. As the influence of the Japanese colonizers increased, weights and measures gradually resembled those used in Meiji Japan. In 1926, the metric system was adopted as the legal metrology. Nevertheless, customary weights and measures were still allowed “for the time being” in everyday life. Such a compromise continued after liberation, even after the introduction of the Measurement Law in 1961. The reasons the Korean government adopted the metric system seem to be the general trend of international society and the export-oriented tactics of the Korean economy, rather than a demand by civil society. Thus, while the government has made an incessant effort to adopt the metric system for nearly a century, the related laws have not been efficiently executed. The use of customary weights and measures was not completely eradicated until 2007 even though their use was outlawed in 1961. This prolonged process of accepting the metric system seems to be the result of a lack of public discussion and social consensus on the metrology system.

Strategy, Incentive Design and Performance: Empirical Evidence

Firms pursuing different business strategies should align these strategies to incentive design. This study uses both archival and survey data on 110 stores of a Japanese high-end bakery chain to provide empirical evidence that misalignment between an organization’s business strategy and incentive design (i.e., weights for financial and non-financial performance measures) adversely affects firm performance. Our results suggest that a decline in the firm performance may be caused by managers’ shifting their focus toward financial measures that are inconsistent with a customer-oriented strategy. Although the firm requires the exclusive usage of non-financial measures in determining promotions, as expected, our results show that financial measures affect managers’ promotions. Additional analyses show that the influence of non-financial measures in promotion decisions becomes less pronounced after the firm shifts to a primarily financial-focused bonus plan.

What is the C/case? C/communism/s, Communist/s, Anti-C/communism/ist/s, and the “C/capitalization Question”

Some time ago I had a conversation with an esteemed colleague who suggested that American Communist History's style sheet requires the exclusive usage of the upper case for “C/communism,” “C/commun...