714 research outputs found
Optimal Investment Under Transaction Costs: A Threshold Rebalanced Portfolio Approach
We study optimal investment in a financial market having a finite number of
assets from a signal processing perspective. We investigate how an investor
should distribute capital over these assets and when he should reallocate the
distribution of the funds over these assets to maximize the cumulative wealth
over any investment period. In particular, we introduce a portfolio selection
algorithm that maximizes the expected cumulative wealth in i.i.d. two-asset
discrete-time markets where the market levies proportional transaction costs in
buying and selling stocks. We achieve this using "threshold rebalanced
portfolios", where trading occurs only if the portfolio breaches certain
thresholds. Under the assumption that the relative price sequences have
log-normal distribution from the Black-Scholes model, we evaluate the expected
wealth under proportional transaction costs and find the threshold rebalanced
portfolio that achieves the maximal expected cumulative wealth over any
investment period. Our derivations can be readily extended to markets having
more than two stocks, where these extensions are pointed out in the paper. As
predicted from our derivations, we significantly improve the achieved wealth
over portfolio selection algorithms from the literature on historical data
sets.Comment: Submitted to IEEE Transactions on Signal Processin
Examination of Existent Propagation Models Over Large Inhomogeneous Terrain Profiles Using Fast Integral Equation Solution
Cataloged from PDF version of article.The accuracyof most widelyused empirical models are investigated
using the spectrallyaccelerated forward-backward (FBSA) method
as a benchmark solution. First, FBSA results are obtained for propagation
over large scale terrain profiles and compared with measurements to assess
the accuracyof FBSA. Then, accuracyof some International Telecommunication
Union (ITU) and Federal Communications Commission (FCC)
propagation models are investigated. It has been observed that, for rural
areas, the prediction of the most recent ITU recommended propagation
model (Rec. 1546) deviates much more than older models do
Computerized Hittite Cuneiform Sign Recognition and Knowledge-Based System Application Examples
The Hittites had lived in Anatolia more than 4000 years ago. The Hittite language is one of the oldest and may be the only one still readable and grammar rules are known member of Indo-European language family. The Hittites had a cuneiform script of their own written on soft clay pads or tablets. Tablets made durable and permanent by baking them after writing with some tools. That is why they could endure for thousands of years buried in the ground. The study of Hittite language has been made manually on the Hittite cuneiform tablets. Unfortunately, field scientists have read and translated only a relatively small number of unearthed tablets. Many more tablets are still waiting under and over ground in Anatolia for reading and translation into various languages. To read and translate the cuneiform signs, using computeraided techniques would be a significant contribution not only to Anatolian and Turkish but also to human history. In this paper, recognition of Hittite cuneiform signs by using computer based image-processing techniques is reported. Additionally, uses of data-mining applications are also included in the paper. Most importantly, the authors also demonstrated feasibility of an expert system on the Hittite cuneiform script
A Model for Hydrogen Thermal Conductivity and Viscosity Including the Critical Point
In order to conduct a thermal analysis of heat transfer to liquid hydrogen near the critical point, an accurate understanding of the thermal transport properties is required. A review of the available literature on hydrogen transport properties identified a lack of useful equations to predict the thermal conductivity and viscosity of liquid hydrogen. The tables published by the National Bureau of Standards were used to perform a series of curve fits to generate the needed correlation equations. These equations give the thermal conductivity and viscosity of hydrogen below 100 K. They agree with the published NBS tables, with less than a 1.5 percent error for temperatures below 100 K and pressures from the triple point to 1000 KPa. These equations also capture the divergence in the thermal conductivity at the critical poin
Characteristic Basis Function Method for Solving Electromagnetic Scattering Problems over Rough Terrain Profiles
Cataloged from PDF version of article.A computationally efficient algorithm, which combines
the characteristic basis function method (CBFM), the
physical optics (PO) approach (when applicable) with the forward
backward method (FBM), is applied for the investigation of electromagnetic
scattering from—and propagation over—large-scale
rough terrain problems. The algorithm utilizes high-level basis
functions defined on macro-domains (blocks), called the characteristic
basis functions (CBFs) that are constructed by aggregating
low-level basis functions (i.e., conventional sub-domain basis functions).
The FBM as well as the PO approach (when applicable)
are used to construct the aforementioned CBFs. The conventional
CBFM is slightly modified to handle large-terrain problems, and
is further embellished by accelerating it, as well as reducing its
storage requirements, via the use of an extrapolation procedure.
Numerical results for the total fields, as well as for the path loss
are presented and compared with either measured or previously
published reference solutions to assess the efficiency and accuracy
of the algorithm
A Deterministic Analysis of an Online Convex Mixture of Expert Algorithms
Cataloged from PDF version of article.We analyze an online learning algorithm that adaptively
combines outputs of two constituent algorithms (or the
experts) running in parallel to model an unknown desired signal.
This online learning algorithm is shown to achieve (and in some
cases outperform) the mean-square error (MSE) performance of
the best constituent algorithm in the mixture in the steady-state.
However, the MSE analysis of this algorithm in the literature
uses approximations and relies on statistical models on the
underlying signals and systems. Hence, such an analysis may not
be useful or valid for signals generated by various real life systems
that show high degrees of nonstationarity, limit cycles and, in
many cases, that are even chaotic. In this paper, we produce
results in an individual sequence manner. In particular, we relate
the time-accumulated squared estimation error of this online
algorithm at any time over any interval to the time-accumulated
squared estimation error of the optimal convex mixture of the
constituent algorithms directly tuned to the underlying signal
in a deterministic sense without any statistical assumptions. In
this sense, our analysis provides the transient, steady-state and
tracking behavior of this algorithm in a strong sense without any
approximations in the derivations or statistical assumptions on
the underlying signals such that our results are guaranteed to
hold. We illustrate the introduced results through examples. © 2012 IEEE
Web-based Integrated Development Environment for Event-Driven Applications
Event-driven programming is a popular methodology for the development of resource-constrained embedded systems. While it is a natural abstraction for applications that interface with the physical world, the disadvantage is that the control flow of a program is hidden in the maze of event handlers and call-back functions. TinyOS is a representative event-driven operating system, designed for wireless sensor networks, featuring a component-based architecture that promotes code reuse. In this paper, we present a web-based model-driven graphical design environment for TinyOS that visualizes the component hierarchy of an application, and captures its eventbased scheduling mechanism. In contrast with existing visual environments, our representation explicitly captures the control flow of the application through events and commands, which makes it easier to understand the program logic than studying the source code. The design environment supports two-way code generation: mapping the visual representation to TinyOS source code, as well as building visual models from existing sources
Systematic Design of edical Capsule Robots
Medical capsule robots that navigate inside the body as diagnostic and interventional tools are an emerging and challenging research area within medical CPSs. These robots must provide locomotion, sensing, actuation, and communication within severe size, power, and computational constraints. This paper presents the first effort for an open architecture, platform design, software infrastructure, and a supporting modular design environment for medical capsule robots to further this research area
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