Opportunistic Interference Mitigation Achieves Optimal Degrees-of-Freedom in Wireless Multi-cell Uplink Networks

We introduce an opportunistic interference mitigation (OIM) protocol, where a user scheduling strategy is utilized in $K$-cell uplink networks with time-invariant channel coefficients and base stations (BSs) having $M$ antennas. Each BS opportunistically selects a set of users who generate the minimum interference to the other BSs. Two OIM protocols are shown according to the number $S$ of simultaneously transmitting users per cell: opportunistic interference nulling (OIN) and opportunistic interference alignment (OIA). Then, their performance is analyzed in terms of degrees-of-freedom (DoFs). As our main result, it is shown that $KM$ DoFs are achievable under the OIN protocol with $M$ selected users per cell, if the total number $N$ of users in a cell scales at least as $\text{SNR}^{(K-1)M}$. Similarly, it turns out that the OIA scheme with $S$($<M$) selected users achieves $KS$ DoFs, if $N$ scales faster than $\text{SNR}^{(K-1)S}$. These results indicate that there exists a trade-off between the achievable DoFs and the minimum required $N$. By deriving the corresponding upper bound on the DoFs, it is shown that the OIN scheme is DoF optimal. Finally, numerical evaluation, a two-step scheduling method, and the extension to multi-carrier scenarios are shown.Comment: 18 pages, 3 figures, Submitted to IEEE Transactions on Communication

A Reading and Writing Placement Test: Design, Evaluation, and Analysis

Placement tests, along with the growing interest in their validation, have become increasingly important in English as a Second Language programs. To this end, the present paper illustrates procedures in designing a placement test and using it to evaluate students’ language ability by means of statistical analysis. 29 participants from three proficiency levels (beginning, intermediate, and advanced) took reading and writing placement test sections. Students’ performance at each proficiency level was analyzed separately and compared across proficiency levels. In addition, analyses of responses on a survey revealed a relationship between language learning attitudes and behaviors exhibited by the participants and their performance on the placement test. Through close examination of the process of placement test design, evaluation, and analysis, this paper provides practical guidelines for reading and writing placement testing

Contextualizing accumulation by dispossession: the state and high-rise apartment clusters in Gangnam, Seoul

In an effort to contribute to the contemporary debates on accumulation by dispossession (ABD), we argue for a closer attention to the link between the state and ABD. We propose contextualizing ABD within the institutionalization of the process of replacing communal property rights with private property rights. In such institutionalization, the state plays a critical role as the final guarantor of property rights. As such, the sociospatial specificities of the state would strongly influence how ABD unfolds and how it is understood. In the empirical part of this article, we use this approach to focus on a specific type of capitalist state—that is, the developmental state—to examine the emergence of apartment-dominated residential landscapes in Gangnam District, Seoul, in the 1970s through the use of ABD. Key Words: accumulation by dispossession and primitive accumulation of capital, developmental state, Gangnam District, high-rise apartments, Seoul, South Korea, vertical accumulation

Management strategies for refractory status epilepticus

Refractory status epilepticus (RSE) is defined as the persistence of either clinical or electrographic seizures despite the administration of appropriate doses of an initial benzodiazepine and suitable second-line antiepileptic drugs (AEDs). The Neurocritical Care Society and the American Epilepsy Society have proposed a treatment paradigm for the management of convulsive status epilepticus (CSE). The third-line therapy in refractory CSE may involve general anesthesia using intravenous midazolam, propofol, or other agents, while recent evidence supports the use of ketamine to manage RSE in both adults and children. However, although these treatment strategies are frequently employed in nonconvulsive status epilepticus (NCSE), the efficacy of AEDs and anesthetics in NCSE has not been thoroughly investigated. Recent evidence has demonstrated the safety and efficacy of newer AEDs, including levetiracetam and lacosamide, in the treatment of status epilepticus (SE) and RSE, which also encompasses NCSE. Use of multiple combinations of various intravenous AEDs can also be considered in NCSE before the administration of general anesthesia. In addition, AEDs alone exhibit limited effectiveness in managing SE for new-onset RSE (NORSE) and its subset, febrile infection-related epilepsy syndrome. Therefore, in cases of refractory status, it is imperative to explore treatment options beyond AEDs, including immunotherapy and the incorporation of a ketogenic diet. The present review suggests treatment approaches for RSE based on subgroups, including CSE, NCSE, and NORSE. A discussion of recent clinical studies on AEDs and anesthetics in the management of RSE, as well as proposed treatment methods for NORSE, is also provided

Can One Achieve Multiuser Diversity in Uplink Multi-Cell Networks?

We introduce a distributed opportunistic scheduling (DOS) strategy, based on two pre-determined thresholds, for uplink $K$-cell networks with time-invariant channel coefficients. Each base station (BS) opportunistically selects a mobile station (MS) who has a large signal strength of the desired channel link among a set of MSs generating a sufficiently small interference to other BSs. Then, performance on the achievable throughput scaling law is analyzed. As our main result, it is shown that the achievable sum-rate scales as $K\log(\text{SNR}\log N)$ in a high signal-to-noise ratio (SNR) regime, if the total number of users in a cell, $N$, scales faster than $\text{SNR}^{\frac{K-1}{1-\epsilon}}$ for a constant $\epsilon\in(0,1)$. This result indicates that the proposed scheme achieves the multiuser diversity gain as well as the degrees-of-freedom gain even under multi-cell environments. Simulation results show that the DOS provides a better sum-rate throughput over conventional schemes.Comment: 11 pages, 3 figures, 2 tables, to appear in IEEE Transactions on Communication

Bacterial community analysis in upflow multilayer anaerobic reactor (UMAR) treating high-solids organic wastes

A novel anaerobic digestion configuration, the upflow multi-layer anaerobic reactor (UMAR), was developed to treat high-solids organic wastes. The UMAR was hypothesized to form multi-layer along depth due to the upflow plug flow; use of a recirculation system and a rotating distributor and baffles aimed to assist treating high-solids influent. The chemical oxygen demand (COD) removal efficiency and methane (CH4) production rate were 89% and 2.10 L CH4/L/day, respectively, at the peak influent COD concentration (110.4 g/L) and organic loading rate (7.5 g COD/L/day). The 454 pyrosequencing results clearly indicated heterogeneous distribution of bacterial communities at different vertical locations (upper, middle, and bottom) of the UMAR. Firmicutes was the dominant (&gt;70%) phylum at the middle and bottom parts, while Deltaproteobacteria and Chloroflexi were only found in the upper part. Potential functions of the bacteria were discussed to speculate on their roles in the anaerobic performance of the UMAR system

Acetonitrile­{3-[bis­(2-pyridyl­methyl-κN)amino-κN]propanol-κO}(perchlorato-κO)copper(II) perchlorate

In the title compound, [Cu(ClO4)(C2H3N)(C15H19N3O)]ClO4, the CuII ion is coordinated by three N atoms and a hydroxyl-O atom of the tetra­dentate ligand, an O atom of a perchlorate ion and an N atom of an acetonitrile ligand giving a tetra­gonally distorted octa­hedral environment around the copper(II) atom. There is an offset inter-complex face-to-face π–π inter­action [centroid–centroid distance = 3.718 (2) Å] involving one of the pyridine rings of the ligand as well as an intra-complex O—H⋯O hydrogen-bonding inter­action between the coordinated hydroxyl group of the ligand and the perchlorate counter-ion

Clinical Characteristics of Monomorphic Post-transplant Lymphoproliferative Disorders

Post-transplant lymphoproliferative disorders (PTLD) are a heterogeneous group of lymphoproliferative disorders associated with immunosuppression and Epstein-Barr virus infection. PTLD is classified into three major categories: early lesions, polymorphic PTLD, and monomorphic PTLD. The majority of monomorphic PTLD cases are non-Hodgkin's lymphoma of B-cell origin. This retrospective study was conducted to investigate the incidence, clinical manifestation, treatment, and outcomes of monomorphic PTLD among 5,817 recipients of solid organ or allogeneic hematopoietic stem cell transplantation from five institutions. Fourteen patients with monomorphic PTLD were identified (male:female 11:3; median age 42.6 yr, range 24-60). The overall incidence rate was 0.24%. The most common disease type was diffuse large B cell lymphoma (n=7). The median time between the transplant and diagnosis of PTLD was 85.8 months. However, all cases of PTLD after allogeneic hematopoietic stem cell transplantation occurred within 1 yr after transplantation. Ten of the 14 patients had EBV-positive tumor. Fourteen patients received combination systemic chemotherapy and four patients were treated with radiation therapy. Ten patients achieved a complete response (CR) and two patients a partial response (PR). The median follow-up period for surviving patients was 36.6 months. Nine patients remain alive (eight CR, one PR). Nine of 11 solid organ transplantations preserved graft function. The present study indicates a lower incidence rate and a longer median time before the development of PTLD than those of previous reports. Careful monitoring was needed after allogeneic hematopoietic stem cell transplantation for PTLD

Thermoelectric properties of graphene incorporated thermoelectric materials

Thermoelectric materials, which can change the waste heat into the usable electricity, are interested in various field of applications such as vehicle, ship, power plane, and so on. To enhance the thermoelectric properties, high electrical conductivity, high Seebeck coefficient, and low thermal conductivity should be conducted, however, the trade-off relation between electronic property and thermal property in terms of carrier concentration could be the bottle-neck on the enhancement of thermoelectric properties of the materials. In this presentation, we discuss with the graphene incorporation in the conventional thermoelectric materials, which could lead to independently control electric and thermal properties