Optimal Dynamic Portfolio with Mean-CVaR Criterion

Value-at-Risk (VaR) and Conditional Value-at-Risk (CVaR) are popular risk measures from academic, industrial and regulatory perspectives. The problem of minimizing CVaR is theoretically known to be of Neyman-Pearson type binary solution. We add a constraint on expected return to investigate the Mean-CVaR portfolio selection problem in a dynamic setting: the investor is faced with a Markowitz type of risk reward problem at final horizon where variance as a measure of risk is replaced by CVaR. Based on the complete market assumption, we give an analytical solution in general. The novelty of our solution is that it is no longer Neyman-Pearson type where the final optimal portfolio takes only two values. Instead, in the case where the portfolio value is required to be bounded from above, the optimal solution takes three values; while in the case where there is no upper bound, the optimal investment portfolio does not exist, though a three-level portfolio still provides a sub-optimal solution

Simultaneous Bidirectional Link Selection in Full Duplex MIMO Systems

In this paper, we consider a point to point full duplex (FD) MIMO communication system. We assume that each node is equipped with an arbitrary number of antennas which can be used for transmission or reception. With FD radios, bidirectional information exchange between two nodes can be achieved at the same time. In this paper we design bidirectional link selection schemes by selecting a pair of transmit and receive antenna at both ends for communications in each direction to maximize the weighted sum rate or minimize the weighted sum symbol error rate (SER). The optimal selection schemes require exhaustive search, so they are highly complex. To tackle this problem, we propose a Serial-Max selection algorithm, which approaches the exhaustive search methods with much lower complexity. In the Serial-Max method, the antenna pairs with maximum "obtainable SINR" at both ends are selected in a two-step serial way. The performance of the proposed Serial-Max method is analyzed, and the closed-form expressions of the average weighted sum rate and the weighted sum SER are derived. The analysis is validated by simulations. Both analytical and simulation results show that as the number of antennas increases, the Serial-Max method approaches the performance of the exhaustive-search schemes in terms of sum rate and sum SER

Co-Evolution of Transportation and Land Use: Modeling HIstorical Dependencies in Land Use and Decision-Making

The interaction between land use and transportation has long been the central issue in urban and regional planning. Models of such interactions provide vital information to support many public policy decisions, such as land supply, infrastructure provision, and growth management. Both the transportation and land use systems exhibit historical dependencies in policy decisions. For instance, the expansion of a roadway today will change travel demand patterns, and make certain other roads more or less likely to be expanded in the future. A specific land supply decision made at one point in time, by changing the relative attractiveness of other areas in the region, can have a profound impact on future land supply decisions. Today’s land use decisions clearly influence future transportation policies and vice versa. This project examines the land use-transportation interaction from an evolutionary perspective — once a certain set of goals are determined and pursued by politicians and planners, their land supply and transportation investment decisions are, to a large extent, driven by their previous decisions and supply-demand dynamics in the urban system. Built upon this recognition of historical dependency and a transportation network growth model previously developed by the P.I., a model of the co-evolution of land use and transportation is proposed in this project. Different from existing integrated land use and transportation models that assume exogenous network investment decisions, the co-evolution model considers both land use growth and transportation network growth as endogenous and market-driven. The central research question is how market and policies translate into transportation facilities and land use developments on the ground. The co-evolution model achieves an Urban Growth Equilibrium, which is a useful concept for planning and policy analysis. An agent-based simulation approach is employed to integrate an existing land use model and the transportation network growth model

Evidence for the formation of ScbR/ScbR2 heterodimers and identification of one of the regulatory targets in Streptomyces coelicolor

The homologous transcriptional regulators ScbR and ScbR2 have previously been identified as γ-butyrolactone (GBL) and antibiotic receptors, respectively. They regulate diverse physiological processes in Streptomyces coelicolor in response to GBL and antibiotic signals. In this study, ScbR and ScbR2 proteins were shown to interact using a bacterial two-hybrid system where adenylate cyclase activity was reconstituted in Escherichia coli BH101. These ScbR/ScbR2 interactions in S. coelicolor were then demonstrated by co-immunoprecipitation. The ScbR/ScbR2 heterodimer was shown to co-exist with their ScbR and ScbR2 respective homodimers. When potential operator targets in S. coelicolor were investigated, the heterodimer was found to bind in the promoter region of sco5158, which however was not a target for ScbR or ScbR2 homodimers. These results revelaed a new mechanism 25 of regulation by ScbR and ScbR2 in S. coelicolor

Intrinsic Modulation Response Modeling and Analysis for Lithographic Vertical-Cavity Surface-Emitting Lasers

Vertical-cavity surface-emitting lasers (VCSELs) have been greatly improved and successfully commercialized over the past few decades owing to their ability to provide both mode and current confinement that enables low energy consumption, high efficiency and high modulation speed. However, further improvement of oxide VCSELs is limited by the nature of the oxide aperture because of self-heating, internal strain and difficulties in precise size control. In this dissertation, VCSELs using lithographic approach are demonstrated to overcome the limitations of oxide VCSELs, in which an intra-cavity phase shifting mesa is applied to define the device size and provide optical mode and electrical current confinement instead of an oxide aperture. A newly developed model of intrinsic modulation response is proposed and analyzed to focus on the thermal limit of the modulation speed of VCSELs. The results show that both the temperature dependent differential gain and stimulated emission rate impact laser speed and the stimulated emission rate dominates the speed limit. Thermal limits of modulation response are compared for oxide and lithographic VCSELs for various sizes. The results predict that the intrinsic modulation response can be significantly increased by using lithographic VCSELs due to low thermal resistance and reduced mode volume while maintaining high efficiency. The intrinsic bandwidth could exceed 100 GHz for a 2-?m-diameter lithographic VCSEL. Combined with low electrical parasitics, it is expected to produce over 100 Gb/s data rate from a single directly modulated laser. VCSELs designed for high speed are discussed and their characteristics are demonstrated

The Mistranslation of James Legge in A Record of Buddhistic Kingdoms from Eco-Environment Translation Theory

Fo Guo Ji, known as A Record of Buddhistic Kingdom, was written by Chinese Monk Fa Xian in the Eastern Jin Dynasty. It is more a travel documentary than an exotic sceneries miracle stories; and place-legends. It has been regarded as one of the most significant classics that probed into the South Asian culture, religion. This paper deals with James Legge’s English translation of Fo Guo Ji from the perspective of translation ecology. Eco-translatology is put forward by Michael Cronin and met with new result when Hong Kong scholar Hu Gengshen put the three properties of language, to be exact, the characteristics of variability of language in both language structure and context is possible, it follows negotiability in the process of using language and the adaptability is required in eco-environment setting. In light of eco-translation theory, this paper aims at exploring the factors influencing James Legge’s English translation by analysizing the text as well as providing a new angle to interpret James Legge’s translation to Chinese classics