Performance limits for FDMA cellular systems described by hypergraphs

The authors present some preliminary material about hypergraphs, including a discussion of what they call random hypergraph multicolorings, a notion which is central to the analysis of frequency-assignment algorithms. They show that for any frequency-assignment algorithm, the carried traffic function must satisfy T(r)⩽T_0(r), where T_0(r) is a simple function that can be computed by linear programming. They give an asymptotic analysis of a class of 'fixed' frequency-assignment algorithms, and show that in the limit as n→∞, these algorithms achieve carried traffic functions that are at least as large as T_1( r), another simple function that can be computed by linear programming. They show that T_0(r)=T_1(r). This common value, denoted by T_(H,p)(r) is the function referred to above. They also describe some of the most important properties of the function TH,p(r), and identify the 'most favorable' traffic patterns for a given hypergraph H

Performance limits for channelized cellular telephone systems

Studies the performance of channel assignment algorithms for “channelized” (e.g., FDMA or TDMA) cellular telephone systems, via mathematical models, each of which is characterized by a pair (H,p), where H is a hypergraph describing the channel reuse restrictions, and p is a probability vector describing the variation of traffic intensity from cell to cell. For a given channel assignment algorithm, the authors define T(r) to be the amount of carried traffic, as a function of the offered traffic, where both r and T(r) are measured in Erlangs per channel. They show that for a given H and p, there exists a function TH,p(r), which can be computed by linear programming, such that for every channel assignment algorithm, T(r) ≤ TH,p(r). Moreover, they show that there exist channel assignment algorithms whose performance approaches TH,p (r) arbitrarily closely as the number of channels increases. As a corollary, they show that for a given (H,p) there is a number r0 , which also can be computed by linear programming, such that if the offered traffic exceeds r0, then for any channel assignment algorithm, a positive fraction of all call requests must be blocked, whereas if the offered traffic is less than r0, all call requests can be honored, if the number of channels is sufficiently large. The authors call r0, whose units are Erlangs per channel, the capacity of the cellular system

Channel assignment in cellular radio

Some heuristic channel-assignment algorithms for cellular systems are described. These algorithms have yielded optimal, or near-optimal assignments, in many cases. The channel-assignment problem can be viewed as a generalized graph-coloring problem, and these algorithms have been developed, in part, by suitably adapting some of the ideas previously introduced in heuristic graph-coloring algorithms. The channel-assignment problem is formulated as a minimum-span problem, i.e. a problem wherein the requirement is to find the minimum bandwidth necessary to satisfy a given demand. Examples are presented, and algorithm performance results are discussed

Change in HER-2/neu Status from Negative to Positive following Treatment in Breast Cancer: A Case Report

Introduction: Approximately 25–30% of breast cancers are assumed to be HER-2/neu positive. It is well known that HER-2/neu-positive cancers after treatment with trastuzumab can become HER-2/neu negative. Change in HER-2/neu status from negative to positive following treatment has not been well studied. We describe a patient with inflammatory breast cancer who was initially HER-2/neu negative but became positive after treatment. A 59-year-old postmenopausal white female saw her surgeon for violaceous discoloration of the left breast for 4 months. The surgeon palpated a mass measuring 6 cm in the patient’s left breast. Additionally, there was violaceous discoloration involving two thirds of the breast. Biopsy of the breast mass and skin revealed inflammatory breast cancer. The tumor was estrogen receptor positive, progesterone receptor positive and HER-2/neu negative. The patient was given four cycles of chemotherapy with cyclophosphamide, doxorubicin and docetaxol. She subsequently underwent a mastectomy, excision of the skin over the chest wall and axillary node dissection. Of the axillary lymph nodes, 14/14 were involved. The tumor was still estrogen receptor positive and progesterone receptor positive, but HER-2/neu was 2+ by immunohistochemistry and amplified at 3.3 as detected by fluorescent in situhybridization. The patient received trastuzumab along with chemotherapy followed by radiation therapy and letrozole. She is currently receiving trastuzumab and letrozole in the adjuvant setting and appears to be doing well. Conclusion: A breast cancer which was initially HER-2/neu negative can become positive following treatment. Therefore, re-biopsy may be necessary during the course of treatment of breast cancer to re-assess the HER-2/neu status. This gives the clinician the opportunity to include drugs like trastuzumab and lapatinib in the treatment of patients with a transformation to HER-2/neu-positive cancer

Time-domain thru-reflect-line (TRL) calibration error assessment and its mitigation and modeling of multilayer printed circuit boards (PCB) with complex area fills

Part 1 for this thesis is on the error assessment of a time-domain (t-TRL) calibration technique. Application of the Thru-Reflect-Line (TRL) calibration to time-domain measurements of S-parameters (t-TRL) can be used for the characterization of the printed circuit boards (PCBs). However, t-TRL calibrated results still have deviations from the reference frequency-domain vector network analyzer (VNA) calibrated results. There are two main sources of errors in the t-TRL calibration. They are random errors, such as an additive noise and jitter, and systematic errors associated with cables, connectors, and port mismatches. This work addresses these two types of errors by proper selection of the number of sampling points, waveform averages, and time record. Methods tried out to eliminate or reduce these errors are detailed in this work. Measurements and simulations were performed for implementing these methods, and the results are explained. A t-TRL calibration automation tool based on TDR/TDT measurements has been developed. Part 2 of this thesis is on the modeling of multilayer PCBs with complex area fills and floating planes. Noise on the power distribution network (PDN) and between the power area fills in multilayer PCBs with complex geometries is a significant concern. Modeling of such PCBs can be done with a cavity model approach. Correlation of a 3D EM solver results with the Multilayer Via Transition Tool (MVTT) results based on cavity model is explained here. Additional modeling and validation was done using the equivalent inductance method --Abstract, page iii

Channel Assignment Algorithms Satisfying Cochannel and Adjacent Channel Reuse Constraints in Cellular Mobile Networks

Improved channel assignment algorithms for cellular networks were designed by modeling the interference constraints in terms of a hypergraph [1]. However, these algorithms only considered cochannel reuse constraints. Receiver filter responses impose restrictions on simultaneous adjacent channel usage in the same cell or in neighboring cells. We first present some heuristics for designing fixed channel assignment algorithms with a minimum number of channels satisfying both cochannel and adjacent channel reuse constraints. An asymptotically tight upper bound for the traffic carried by the system in the presence of arbitrary cochannel and adjacent channel use constraints was developed in [2]. However, this bound is computationally intractable even for small systems like a regular hexagonal cellular system of 19 cells. We have obtained approximations to this bound using the optimal solutions for cochannel reuse constraints only and a further graph theoretic approach. Our approximations are computationally much more efficient and have turned out to track very closely the exact performance bounds in most cases of interest

Fairness in Cellular Mobile Networks

Channel allocation algorithms for channelized cellular systems are discussed from a new perspective, viz., fairness of allocation. The concepts of relative and absolute fairness are introduced and discussed. It will be shown that under certain reasonable assumptions, there exists an absolute (max-min) fair carried traffic intensity vector (a vector describing the traffic carried in the cells of the system). We also show that this vector is unique. We describe some properties of the max-min fair carried traffic intensity vector in an asymptotic limit where the traffic and the number of channels are scaled together. For each traffic pattern, we determine a fixed channel allocation which attains this max-min fair carried traffic intensity vector independent of the value of the offered traffic, in the same asymptotic limit. Finally, we discuss a tradeoff between being max-min fair and trying to maximize revenue. We conclude this correspondence by discussing some possible extensions of our work

Deep Transcriptomic Profiling of M1 Macrophages Lacking Trpc3

In previous studies using mice with macrophage-specific loss of TRPC3 we found a significant, selective effect of TRPC3 on the biology of M1, or inflammatory macrophages. Whereas activation of some components of the unfolded protein response and the pro-apoptotic mediators CamkII and Stat1 was impaired in Trpc3-deficient M1 cells, gathering insight about other molecular signatures within macrophages that might be affected by Trpc3 expression requires an alternative approach. In the present study we conducted RNA-seq analysis to interrogate the transcriptome of M1 macrophages derived from mice with macrophage-specific loss of TRPC3 and their littermate controls. We identified 160 significantly differentially expressed genes between the two groups, of which 62 were upregulated and 98 downregulated in control vs. Trpc3-deficient M1 macrophages. Gene ontology analysis revealed enrichment in processes associated to cellular movement and lipid signaling, whereas the enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways included networks for calcium signaling and cell adhesion molecules, among others. This is the first deep transcriptomic analysis of macrophages in the context of Trpc3 deficiency and the data presented constitutes a unique resource to further explore functions of TRPC3 in macrophage biology.Fil: Kumarasamy, Sivarajan. University of Toledo; Estados UnidosFil: Solanki, Sumeet. University of Toledo; Estados UnidosFil: Atolagbe, Oluwatomisin T.. University of Toledo; Estados UnidosFil: Joe, Bina. University of Toledo; Estados UnidosFil: Birnbaumer, Lutz. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Instituto de Investigaciones Biomédicas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; ArgentinaFil: Vazquez, Guillermo. University of Toledo; Estados Unido