An n - L(k, k-1, ..., 1) labeling of a simple graph G is a mapping f: V(G) → {0, 1, ..., n} such that |f(u) - f(v)| ≥ k+1 - d(u,v), for all u,v∈V(G), where d(u,v) is the length of the shortest path connecting u and...
详细信息
In this paper we present the development of a Variable Structure Interacting Multiple Model (VS-IMM) estimator for tracking groups of ground targets on constrained paths using Moving Target Indicator (MTI) reports obt...
详细信息
ISBN:
(纸本)0819428221
In this paper we present the development of a Variable Structure Interacting Multiple Model (VS-IMM) estimator for tracking groups of ground targets on constrained paths using Moving Target Indicator (MTI) reports obtained from an airborne sensor. The targets are moving along a highway, with varying inter-visibility (obscuration) due to changing terrain conditions. In addition, the roads can branch, merge or cross. Some of the targets may also move in an open field. This constrained motion estimation problem is handled using an IMM estimator with varying mode sets depending on the topography. The number of models in the IMM estimator, their types and their parameters are modified adaptively, in real-time, based on the estimated position of the target and the corresponding road/visibility conditions. This topography-based variable structure mechanism eliminates the need for carrying all the possible models throughout the entire tracking period as in the standard IMM estimator, improving performance and reducing computational load.
Many tracking systems have the requirement to transfer information about a particular tracked object between two systems. The general approach to this involves generation of an object map by the system designating the...
详细信息
ISBN:
(纸本)081945351X
Many tracking systems have the requirement to transfer information about a particular tracked object between two systems. The general approach to this involves generation of an object map by the system designating the particular track followed by receipt of the map and correlation to the local track picture of the second system. Correlation performance is in general limited by a number of factors: random track errors added by each system, miss-registration of the two systems' coordinate frames, and miss-match between the numbers of objects tracked by the two systems. Two correlation algorithms are considered for this problem: Global Nearest Neighbor (GNN) and Global Nearest Pattern (GNP). Four basic failure modes are identified for the GNP formulation, and three of these explain failures in the GNN formulation. Analytic expressions are derived for each of these modes, and a comparison of each to Monte-Carlo experiment is provided to demonstrate overall validity.
The paper addresses the Multi-Depot Vehicle Routing Problem (MDVRP) motivated by its practical relevance and considerable difficulty. Specifically, the work focuses on the assignment of customers to depots, one of the...
详细信息
The paper addresses the Multi-Depot Vehicle Routing Problem (MDVRP) motivated by its practical relevance and considerable difficulty. Specifically, the work focuses on the assignment of customers to depots, one of the phases carried out to solve the MDVRP. Many authors have tackled this problem, and there are different heuristics to perform this task. This paper presents two new heuristics for this important phase of the MDVRP. Both heuristics are simple to implement and are fast in their execution. Furthermore, experimental results showed that the achieved solutions are comparable to those of some of the most important heuristics for this task.
Matching for several nominal covariates with many levels has usually been thought to be difficult because these covariates combine to form an enormous number of interaction categories with few if any people in most su...
详细信息
Matching for several nominal covariates with many levels has usually been thought to be difficult because these covariates combine to form an enormous number of interaction categories with few if any people in most such categories. Moreover, because nominal variables are not ordered, there is often no notion of a "close substitute" when an exact match is unavailable. In a case-control study of the risk factors for readmission within 30 days of surgery in the Medicare population, we wished to match for 47 hospitals, 15 surgical procedures grouped or nested within 5 procedure groups, two genders, or 47 x 15 x 2 = 1410 categories. In addition, we wished to match as closely as possible for the continuous variable age (65-80 years). There were 1380 readmitted patients or cases. A fractional factorial experiment may balance main effects and low-order interactions without achieving balance for high-order interactions. In an analogous fashion, we balance certain main effects and low-order interactions among the covariates;moreover, we use as many exactly matched pairs as possible. This is done by creating a match that is exact for several variables, with a close match for age, and both a "near-exact match" and a "finely balanced match" for another nominal variable, in this case a 47 x 5 = 235 category variable representing the interaction of the 47 hospitals and the five surgical procedure groups. The method is easily implemented in R.
暂无评论