Degrees of Freedom of Uplink-Downlink Multiantenna Cellular Networks

An uplink-downlink two-cell cellular network is studied in which the first base station (BS) with $M_1$ antennas receives independent messages from its $N_1$ serving users, while the second BS with $M_2$ antennas transmits independent messages to its $N_2$ serving users. That is, the first and second cells operate as uplink and downlink, respectively. Each user is assumed to have a single antenna. Under this uplink-downlink setting, the sum degrees of freedom (DoF) is completely characterized as the minimum of $(N_1N_2+\min(M_1,N_1)(N_1-N_2)^++\min(M_2,N_2)(N_2-N_1)^+)/\max(N_1,N_2)$, $M_1+N_2,M_2+N_1$, $\max(M_1,M_2)$, and $\max(N_1,N_2)$, where $a^+$ denotes $\max(0,a)$. The result demonstrates that, for a broad class of network configurations, operating one of the two cells as uplink and the other cell as downlink can strictly improve the sum DoF compared to the conventional uplink or downlink operation, in which both cells operate as either uplink or downlink. The DoF gain from such uplink-downlink operation is further shown to be achievable for heterogeneous cellular networks having hotspots and with delayed channel state information.Comment: 22 pages, 11 figures, in revision for IEEE Transactions on Information Theor

Multi-Agent Bilateral Bargaining with Endogenous Protocol

Consider a multilateral bargaining problem where negotiation is conducted by a sequence of bilateral bargaining sessions. We are interested in an environment where bargaining protocols are determined endogenously. During each bilateral bargaining session of Rubinstein (1982), two players negotiate to determine who leaves the bargaining and with how much. A player may either make an offer to his opponent who would then leave the game or demand to leave the game himself. Players' final distribution of the pie and a bargaining protocol constitute an equilibrium outcome. When discounting is not too high, we find multiple subgame perfect equilibrium outcomes, including inefficient ones. As the number of players increases, both the set of discount factors that support multiple equilibrium outcomes and the set of the first proposing player's equilibrium shares are enlarged. The inefficiency in equilibrium remains even as the discount factor goes to one.Multilateral bargaining

The Eeckhout Condition and the Subgame Perfect Implementation of Stable Matching

We investigate an extensive form sequential matching game of perfect information. We show that the subgame perfect equilibrium of the sequential matching game leads to the unique stable matching when the Eeckhout Condition (2000) for existence of a unique stable matching holds, regardless of the sequence of agents. This result does not extend to preferences that violate the Eeckhout Condition, even if there is a unique stable matching.Matching; unique stable matching; subgame perfect equilibrium

A comparison of the food habits of juvenile Pacific cod and walleye pollock in the southeast Bering Sea

Thesis (M.S.) University of Alaska Fairbanks, 1985The food habits of juvenile Pacific cod, Gadus macrocephalus, and walleye pollock, Theragra chalcogramma, collected in July and August in 1981 through 1983 in the eastern Bering Sea, were compared in relation to some morphological characteristics. The fishes' gill rakers were counted, the distances between gill rakers were measured, and the stomach tissue weight was measured. The stomach contents were analysed by occurrence, number and volume. It was found that the fishes' gill structures were related to size-selective predation in both fishes. Pollock utilized small zooplankton and cod large zooplankton. Food competition was expected when fishes are smaller than 40 mm TL as indicated by high values in proportional similarity. However, food competition decreases as the fishes grow and develop distinct size-selective predation habits. Prey composition in the stomachs reflected the regional differences of local oceanographic environments

Adaptations of Pseudomonas aeruginosa to the Cystic Fibrosis Lung Environment Can Include Deregulation of zwf, Encoding Glucose-6-Phosphate Dehydrogenase

Cystic fibrosis (CF) patients are highly susceptible to chronic pulmonary disease caused by mucoid Pseudomonas aeruginosa strains that overproduce the exopolysaccharide alginate. We showed here that a mutation in zwf, encoding glucose-6-phosphate dehydrogenase (G6PDH), leads to a 90% reduction in alginate production in the mucoid, CF isolate, P. aeruginosa FRD1. The main regulator of alginate, sigma-22 encoded by algT (algU), plays a small but demonstrable role in the induction of zwf expression in P. aeruginosa. However, G6PDH activity and zwf expression were higher in FRD1 strains than in PAO1 strains. In PAO1, zwf expression and G6PDH activity are known to be subject to catabolite repression by succinate. In contrast, FRD1 zwf expression and G6PDH activity were shown to be refractory to such catabolite repression. This was apparently not due to a defect in the catabolite repression control (Crc) protein. Such relaxed control of zwf was found to be common among several examined CF isolates but was not seen in other strains of clinical and environmental origin. Two sets of clonal isolates from individual CF patient indicated that the resident P. aeruginosa strain underwent an adaptive change that deregulated zwf expression. We hypothesized that high-level, unregulated G6PDH activity provided a survival advantage to P. aeruginosa within the lung environment. Interestingly, zwf expression in P. aeruginosa was shown to be required for its resistance to human sputum. This study illustrates that adaptation to the CF pulmonary environment by P. aeruginosa can include altered regulation of basic metabolic activities, including carbon catabolism. Originally published Journal of Bacteriology, Vol. 187, No. 22, Nov 200

Creating Intelligent Computational Edge through Semantic Mediation

This research proposes semantic mediation based on reasoning and the first order logic for mediating the best possible configuration of Computational Edge, relevant for software applications which may benefit for running computations with proximity to their data sources. The mediation considers the context in which these applications exist and exploits the semantic of that context for decision making on where computational elements should reside and which data they should use. The application of semantic mediation could address the initiative to accommodate algorithms from predictive and learning technologies, push AI towards computational edges and potentially contribute towards creating a computing continuum