Two similar detached binary systems: AT and AZ camelopardalis

Photoelectric BV observations of AT Cam are presented. The O-C diagram of the times of light minimum shows a probable long-term variation in the period. Photometric solutions using the Wilson-Devinney method were made for both AT Cam and AZ Cam. Both are found to be detached systems, but the components are close to the critical surfaces. For AT Cam, there are two probable solutions around the mass-ratio, q=0.60 and 3.45, both giving a detached configuration. For AZ Cam, q=1.52, the primary eclipse is a partial occultation at an inclination i=80.5°. A brief discussion is given on their evolutionary stages, based on the fractional radii and the mass-ratios obtained.     

An adaptive compromise programming method for multi-objective path optimization

Network routing problems generally involve multiple objectives which may conflict one another. An effective way to solve such problems is to generate a set of Pareto-optimal solutions that is small enough to be handled by a decision maker and large enough to give an overview of all possible trade-offs among the conflicting objectives. To accomplish this, the present paper proposes an adaptive method based on compromise programming to assist decision makers in identifying Pareto-optimal paths, particularly for non-convex problems. This method can provide an unbiased approximation of the Pareto-optimal alternatives by adaptively changing the origin and direction of search in the objective space via the dynamic updating of the largest unexplored region till an appropriately structured Pareto front is captured. To demonstrate the efficacy of the proposed methodology, a case study is carried out for the transportation of dangerous goods in the road network of Hong Kong with the support of geographic information system. The experimental results confirm the effectiveness of the approach.     

An intelligent expert system shell for knowledge-based Geographical Information Systems: 1. The tools

Abstract

An intelligent expert system shell for the development of knowledge-based geographical information systems (GIS) is examined in this two-part article. Basic concepts and the overall architecture of the shell are discussed in the present part. Fuzzy logic and expert systems technology are demonstrated to be appropriate methods for approximating human reasoning and enhancing the level of intelligence in GIS. The shell can be employed as an effective and efficient tool for developing knowledge-based GIS.     

A rough set approach to the discovery of classification rules in spatial data

This paper proposes a novel rough set approach to discover classification rules in real‐valued spatial data in general and remotely sensed data in particular. A knowledge induction process is formulated to select optimal decision rules with a minimal set of features necessary and sufficient for a remote sensing classification task. The approach first converts a real‐valued or integer‐valued decision system into an interval‐valued information system. A knowledge induction procedure is then formulated to discover all classification rules hidden in the information system. Two real‐life applications are made to verify and substantiate the conceptual arguments. It demonstrates that the proposed approach can effectively discover in remotely sensed data the optimal spectral bands and optimal rule set for a classification task. It is also capable of unraveling critical spectral band(s) discerning certain classes. The framework paves the road for data mining in mixed spatial databases consisting of qualitative and quantitative data.     

Imposex levels in the dogwhelk Nucella lapillus (L.)--continuing improvement at high latitudes

In 1990, restrictions on the use of tributyltin (TBT)-based antifouling paints were implemented in Iceland. A previous study showed that the level of imposex in the dogwhelk, Nucella lapillus, in Icelandic waters had decreased significantly between 1992 and 1998. In this study, we repeated the survey on imposex in N. lapillus at 33 locations from the Icelandic coast in 2003. The results indicated that both Vas Deferens Sequence Index (VDSI) and Relative Penis Size Index (RPSI) had further declined in 13 locations since 1998. Among these 13 sites, RPSI was reduced to zero in five cases. While improvements from 1992/1993 to 1998 were seen in reduced levels of imposex near both large and small harbours, the pattern from 1998 to 2003 was somewhat different, with improvement mainly observed near smaller harbours. No significant changes in imposex levels near larger harbours occurred over this period. Although the imposex levels still remain high near the large harbour complexes in Reykjavík and Hafnarfjörður, it is evident that regulations, including the use of less toxic antifouling paints and community action, have lead to substantial improvements in the marine environment of Iceland. International Maritime Organisation’s ban on the application of TBT after 2003 is apparently necessary to allow further improvements in larger harbours. The environmental effects of new antifoulants replacing TBT need to be further evaluated.     

Applying chaos to radar detection in an ocean environment: anexperimental study

Ship navigation through ice-infested waters is a problem of deep concern to the oil exploration industry of Northern countries. Conventional marine radars do not perform satisfactorily in detecting small targets such as small pieces of iceberg. This paper reports a new method for detection in an ocean environment. The approach is based on the recent observation that sea clutter, radar echoes from the sea surface, can be modeled as a nonlinear deterministic dynamical system which can be used as an alternative to the conventional stochastic process. Based on this model, detection in sea clutter is considered as dynamical system classification instead of statistical hypothesis testing. Two dynamical detection methods are proposed. The first one uses a dynamical invariant called the attractor dimension to distinguish a target from a pure clutter process. The second approach tries to detect the existence of a target by observing the “difference” of the motion of the target and the clutter process. To show the validity of the idea of dynamical detection in sea clutter, real sea clutter, and target data were used in this study     

A new photometric study of the binary U Pegasi

Over four hundred photoelectric observations of U Peg in B and V were secured with a 0.6M reflector at Beijing Observatory in 1978. Four times of minima were determined. A period study of the times of minima from 1896 to 1980 was performed. The system was found to have a secular period decrease, Δp/p of ?1.32 ¢ 10^?1 or ?4.16 × 10^?3 sec/yr, as well as a short term (17 years) sinusoidal oscillation with a semi-amplitude of 0.00323 day. It is suggested that oscillating term is caused by the light-time effect of an unseen third body. The third body may be a M6 main sequence star with a mass of 0.16 M_⊙. The longterm secular change in period may be associated with slow mass transfer.The analysis of the 1978 light curves together with the 1958 light curves of Binnendijk suggest that the system U Peg has an overcontact configuration of about 9%. It has the characteristics of a W-type W UMa system. The photometric mass ratio, $\text{m}{}_2\text{m}{}_1$, is between 3 and 2.5. If we correct the Struve et al. γ-velocity from 0 km/sec to about ?40 km/sec the estimated spectroscopic mass ratio would agree with the photoelectric value. Based on the above assumption the absolute dimensions of U Peg are of 0.6 and 1.8 M_⊙ and of 0.8 and 1.4 R_⊙, for components 1 and 2 respectively. The physical dimensions indicate that the components are main sequence stars.     

Modelling for registration of remotely sensed imagery when reference control points contain error

1 Introduction The process of remotely sensed data acquisition isaffected by factors such as the rotation of the earth, finite scan rate of some sensors, curvature of the earth, non-ideal sensor, variation in platform altitude, attitude, velocity, etc.[1]. One important procedurewhich should be done prior to analyzing remotely sensed data, is geometric correction (image to map) or registration (image to image) of remotely sensed data. The purpose of geometric correction or registration is to e…     

Seismic upgrade of hydraulic fill dam by buttressing

The vulnerability of hydraulic fill dams under strong earthquake shaking has long been recognized. When located in areas of high seismic hazard, seismic upgrading of these types of dams is often required to meet current dam safety standards. Selection of an appropriate design concept for seismic upgrading of such dams requires careful consideration of seismically induced deformations when the hydraulic fill is to remain as part of the dam. This paper presents a case history of the seismic upgrade of Butt Valley Dam, a hydraulic fill dam located in Northern California. The dam was strengthened to withstand the Maximum Credible Earthquake (MCE) by buttressing of its upstream and downstream slopes. The paper discusses the evaluation of alternatives to upgrade the dam, the design criteria, and the design and analysis of the seismic upgrade. It is shown that a conservative and robust design was developed based on well-established engineering principles and multiple lines of defense, and sound use of analysis procedures including finite-difference non-linear dynamic deformation analyses.     

Analysing regional industrialisation in Jiangsu province using geographically weighted regression

 Industry is the most important sector in the Chinese economy. To identify the spatial interaction between the level of regional industrialisation and various factors, this paper takes Jiangsu province of China as a case study. To unravel the existence of spatial nonstationarity, geographically weighted regression (GWR) is employed in this article. Conventional regression analysis can only produce `average' and `global' parameter estimates rather than `local' parameter estimates which vary over space in some spatial systems. Geographically weighted regression (GWR), on the other hand, is a relatively simple, but useful new technique for the analysis of spatial nonstationarity. Using the GWR technique to study regional industrialisation in Jiangsu province, it is found that there is a significant difference between the ordinary linear regression (OLR) and GWR models. The relationships between the level of regional industrialisation and various factors show considerable spatial variability. Received: 4 April 2001 / Accepted: 17 November 2001