基于线性相位近似的SOQPSK-TG信号同步算法

SOQPSK-TG （Telemetry Group version of Shaped Offset Quadrature Phase Shift Key）具有良好的频率利用率和功率利用率,广泛应用于无线通信系统当中。在连续通信模式下,SOQPSK-TG信号的同步主要采用直接判决算法。为进一步降低算法复杂度,推导了基于线性相位近似的最大似然估计误差鉴别器,理论上分析了算法估计性能,并搭建了简化的接收模型。通过仿真证明了算法在估计性能上优于脉冲幅度调制方法,算法误码率接近理论性能。     

Analysis of Error with Malliavin Calculus: Application to Hedging

The aim of this paper is to compute the quadratic error of a discrete time-hedging strategy in a complete multidimensional model. This result extends that of Gobet and Temam (2001) and Zhang (1999) . More precisely, our basic assumption is that the asset prices satisfy the d -dimensional stochastic differential equation   dXⁱ_t = Xⁱ_t ( bⁱ ( X_t ) dt +σ _{i , j} ( X_t ) dW^j_t )  . We precisely describe the risk of this strategy with respect to n , the number of rebalancing times. The rates of convergence obtained are     for any options with Lipschitz payoff and  1/ n ^1/4  for options with irregular payoff.     

How an innovation is formed: A case study of Japanese word processors

An innovation is formed in the social system through the diffusion process, and artifacts that embody the innovation alter their aspects considerably. This study proposes an innovation-diffusion model on the assumption that an innovation interacts with a social system, which shows dynamic and self-organizing characteristics. That is, firstly, an innovation appears that overthrows the existing technological paradigm. Secondly, after the appearance of an innovation, engineers or relevant professionals witnessing the innovation conduct various kinds of trial and error to compete with each other. Thirdly, under passing through the turmoil period, the social system in which an innovation has been implemented becomes changing its structure. Fourthly, once an innovation has surpassed the irreversible phase, obtaining the dominant design, it becomes embedded into the social system. In order to verify the model, I refer to the diffusion process of the Japanese word processors into the Japanese society around 1980s. Following the result of this study, this paper points out that the diffusion theory should be reconsidered, especially about the meanings of the critical mass, the dichotomy of the innovator-imitator model, and so on. Besides, strategic planners or policy makers would do well to construct innovation strategies or technology policies to implement the innovation by affecting such factors as the internal and external influence factors and the population of the potential adopters.     

Industrial Policy and Technology Diffusion: Evidence from Paper Making Machinery in Indonesia

In this paper, we analyze the diffusion and adoption of paper making machinery in the Indonesian pulp and paper industry, from 1923 till 2000. We develop a machine level index of technological sophistication (mach), which measures the technological distance of each paper machine to the world technological frontier. The data reveal a pattern of rapid technological catch up. But catch up was not an industrywide phenomenon. Some modern firms installed state-of-the-art machinery, while others installed older vintages. The paper argues that industrial policy has played an important role in the speed and nature of diffusion of paper making machinery.     

When does the majority become a majority? Empirical analysis of the time at which main market adopters purchase the bulk of our sales

The idea of a dual-market structure in the early stages of a product's life cycle has become one of the most widely accepted ideas among new product marketing practitioners in the past decade. Concepts such as “Early Market/Main Market” and “Visionaries/Pragmatists” have entered the lexicon of high-tech executives to express the notion that the market for new products is composed of early and main markets with a discontinuity in the diffusion process in between them. Moreover, these concepts have been at least partially tested and verified in the marketing academic literature in the past few years.We extend this branch of research by investigating the timing issues in dual-market cases. We define Change-of-Dominance Time (CD-Time) as the number of years it takes main market adopters to outnumber early market adopters. We empirically investigate this timing issue on a comprehensive data set of new product sales in the consumer electronics industry. We find that regarding explanatory determinants of CD-Time, external influence, such as advertising, to the early market is the most important explanatory variable.We examine the relationship between CD-Time and other early product life cycle phenomena: Takeoff, Saddle, and Rogers' size of adopter categories. We found relatively high correlations between these phenomena and CD-Time.The answer to the question “When does the majority become a majority?” is indeed “at 16%”! In a dual-market setting, the average time at which the main market outnumbers the early market is when 16% of the market has already adopted the product. In terms of time, in 75% of the cases the majority becomes a majority in 5 to 10 years.     

Pricing Barrier Options with Time–Dependent Coefficients

We consider the problem of pricing derivative securities which involve a barrier clause. We give general techniques to calculate, or estimate accurately, barrier option prices, using methods for estimating diffusion process boundary hitting times. The solution gives a simple, easy–to–use, method for calculating barrier option prices.     

On a stochastic approximation procedure based on averaging

Based on the idea of averaging a new stochastic approximation algorithm has been proposed by Bather (1989), which shows a preferable performance for small to moderate sample sizes. In the present paper an almost sure representation is established for this procedure, which gives the optimal rate of convergence with minimal asymptotic variance. Work partly supported by the research grant Ku719/2-1 of the Deutsche Forschungsgemeinschaft     

DRAMs, fiber and energy compared with three models of market penetration

When a new technology is introduced in the market, this technology generally follows an S-shaped curve, especially if measured on a relative (market share) basis. Marchetti and Nakicenovic and Norton and Bass have modeled the multivariant case of various technologies introduced at different times. A new, simple and flexible model has been proposed based on potential penetration. Potential penetration is penetration on the assumption that no other new technology will enter the market. In a stable competitive environment, potential penetration curves are typically positively sloped S-curves. The new model gives a good fit in markets with a limited number of competitors, which are capable of totally cannibalizing previous generations of technologies. It also fits well with markets with many competitors in a competitive equilibrium situation. Examples are the Dynamic Random Access Memory chips (DRAMs), fiber and energy market. The new model features fewer variables compared with existing models and can readily be adapted to technological processes with time varying parameters, which is particularly important in volatile competitive markets.     

A Partially Observed Model for Micromovement of Asset Prices with Bayes Estimation via Filtering

A general micromovement model that describes transactional price behavior is proposed. The model ties the sample characteristics of micromovement and macromovement in a consistent manner. An important feature of the model is that it can be transformed to a filtering problem with counting process observations. Consequently, the complete information of price and trading time is captured and then utilized in Bayes estimation via filtering for the parameters. The filtering equations are derived. A theorem on the convergence of conditional expectation of the model is proved. A consistent recursive algorithm is constructed via the Markov chain approximation method to compute the approximate posterior and then the Bayes estimates. A simplified model and its recursive algorithm are presented in detail. Simulations show that the computed Bayes estimates converge to their true values. The algorithm is applied to one month of intraday transaction prices for Microsoft and the Bayes estimates are obtained.     

STOCK LIQUIDATION VIA STOCHASTIC APPROXIMATION USING NASDAQ DAILY AND INTRA-DAY DATA

By focusing on computational aspects, this work is concerned with numerical methods for stock selling decision using stochastic approximation methods. Concentrating on the class of decisions depending on threshold values, an optimal stopping problem is converted to a parametric stochastic optimization problem. The algorithms are model free and are easily implementable on-line. Convergence of the algorithms is established, second moment bound of estimation error is obtained, and escape probability from a neighborhood of the true parameter is also derived. Numerical examples using both daily closing prices and intra-day data are provided to demonstrate the performance of the algorithms.