Minimum common string partition revisited

Minimum Common String Partition (MCSP) has drawn much attention due to its application in genome rearrangement. In this paper, we investigate three variants of MCSP: MCSP ^c , which requires that there are at most c elements in the alphabet; d-MCSP, which requires the occurrence of each element to be bounded by d; and x-balanced MCSP, which requires the length of blocks being in range (n/k?x,n/k+x), where n is the length of the input strings, k is the number of blocks in the optimal common partition and x is a constant integer. We show that MCSP ^c is NP-hard when c≥2. As for d-MCSP, we present an FPT algorithm which runs in O ^?((d!)^2k ) time. As it is still unknown whether an FPT algorithm only parameterized on k exists for the general case of MCSP, we also devise an FPT algorithm for the special case x-balanced MCSP parameterized on both k and x.     

Sparse multipartite graphs as partition universal for graphs with bounded degree

For graphs G and H, let \(G\rightarrow (H,H)\) signify that any red/blue edge coloring of G contains a monochromatic H as a subgraph. Denote \(\mathcal {H}(\Delta ,n)=\{H:|V(H)|=n,\Delta (H)\le \Delta \}\). For any \(\Delta \) and n, we say that G is partition universal for \(\mathcal {H}(\Delta ,n)\) if \(G\rightarrow (H,H)\) for every \(H\in \mathcal {H}(\Delta ,n)\). Let \(G_r(N,p)\) be the random spanning subgraph of the complete r-partite graph \(K_r(N)\) with N vertices in each part, in which each edge of \(K_r(N)\) appears with probability p independently and randomly. We prove that for fixed \(\Delta \ge 2\) there exist constants r, B and C depending only on \(\Delta \) such that if \(N\ge Bn\) and \(p=C(\log N/N)^{1/\Delta }\), then asymptotically almost surely \(G_r(N,p)\) is partition universal for \(\mathcal {H}(\Delta ,n)\).     

A rooted-forest partition with uniform vertex demand

A rooted-forest is the union of vertex-disjoint rooted-trees. Suppose we are given a graph G=(V,E), a collection {R ₁,??,R _k } of k root-sets (i.e., vertex-sets), and a positive integer d. We prove a necessary and sufficient condition for G to contain k edge-disjoint rooted-forests F ₁,??,F _k with root-sets R ₁,??,R _k such that each vertex is spanned by exactly d of F ₁,??,F _k .     

Considerations for grief interventions: eras of witnessing with families

This article describes research that was conducted to articulate interventions with families experiencing grief. Using an interpretive methodology framed by philosophical hermeneutics allowed for a depth of understanding of these therapeutic conversations. The research findings offer explanations of the role of time in relation to grief, particularly the timing of interventions, and describe the significance of working with multiple family members during therapeutic interventions. This research was unique in that it approached grief counseling with a family focus, the participants were interviewed for this study several years after the therapeutic encounter, and the underlying theoretical framework for the interventions focused on grief as a lifelong, life-changing experience, rather than a finite, pathology-laden event.     

Heterochromatic tree partition number in complete multipartite graphs

The heterochromatic tree partition number of an \(r\) -edge-colored graph \(G,\) denoted by \(t_r(G),\) is the minimum positive integer \(p\) such that whenever the edges of the graph \(G\) are colored with \(r\) colors, the vertices of \(G\) can be covered by at most \(p\) vertex disjoint heterochromatic trees. In this article we determine the upper and lower bounds for the heterochromatic tree partition number \(t_r(K_{n_1,n_2,\ldots ,n_k})\) of an \(r\) -edge-colored complete \(k\) -partite graph \(K_{n_1,n_2,\ldots ,n_k}\) , and the gap between upper and lower bounds is at most one.     

On the vertex characterization of single-shape partition polytopes

Given a partition of distinct d-dimensional vectors into p parts, the partition sum of the partition is the sum of vectors in each part. The shape of the partition is a p-tuple of the size of each part. A single-shape partition polytope is the convex hull of partition sums of all partitions that have a prescribed shape. A partition is separable if the convex hull of its parts are pairwise disjoint. The separability of a partition is a necessary condition for the associated partition sum to be a vertex of the single-shape partition polytope. It is also a sufficient condition for d=1 or p=2. However, the sufficiency fails to hold for d≥3 and p≥3. In this paper, we give some geometric sufficient conditions as well as some necessary conditions of vertices in general d and p. Thus, the open case for d=2 and p≥3 is resolved.     

Cost models for evaluating virtual design strategies in multicycle product families

Rapid technological change and increased competition are forcing firms to compress the time it takes to develop product families and rapidly realize innovations among successive family members (models). Competition in rapidly changing high-variety markets requires effective management of design information across successive generations of products as well as in the same product generation. This paper considers two complementary approaches to design information management: virtual design and modular design. Virtual design describes the abstraction hierarchy used to represent product function. Modular design describes the hierarchy of physical realizations of the product and leads to a group technology approach to manufacturing. An analytical model is used to describe the impact of design management strategy characterized by investment in tools and infrastructure for virtual design and group technology on product development costs. This model provides insight into the impacts on costs of the mix of standard and revised parts in a product family. Virtual design has greatest impact on cost when there is a large proportion of parts revision, while group technology has most impact on cost when large numbers of standard parts are re-used. Effective management strategy for high variety rapidly changing products should combine both of these approaches and emphasize compatible organizational methods and technology integration.     

Small grid drawings of planar graphs with balanced partition

In a grid drawing of a planar graph, every vertex is located at a grid point, and every edge is drawn as a straight-line segment without any edge-intersection. It is known that every planar graph G of n vertices has a grid drawing on an (n?2)×(n?2) or (4n/3)×(2n/3) integer grid. In this paper we show that if a planar graph G has a balanced partition then G has a grid drawing with small grid area. More precisely, if a separation pair bipartitions G into two edge-disjoint subgraphs G ₁ and?G ₂, then G has a max?{n ₁,n ₂}×max?{n ₁,n ₂} grid drawing, where n ₁ and n ₂ are the numbers of vertices in G ₁ and?G ₂, respectively. In particular, we show that every series-parallel graph G has a (2n/3)×(2n/3) grid drawing and a grid drawing with area smaller than 0.3941n ² (<(2/3)² n ²).     

基金系内部交叉补贴行为研究

从基金基本特征—费用、业绩和年龄入手,利用面板数据固定效应模型对基金系内部交叉补贴行为进行考察.发现基金系内部老基金对新基金、高业绩基金对低业绩基金交叉补贴行为最显著,对费用途径考察结果不明显.文章还对基金系特征与基金系内部交叉补贴途径进行研究,发现大规模基金系与小规模基金系相比,内部交叉补贴现象更为明显.     

The Delphi method and urbanization

In this article the author puts forward his reasons for wishing to use the Delphi method for a future forecasting programme in Canada. He argues that the results of such a survey should be of great assistance in the field of urban affairs.     

Planning end-of-life care for patients with dementia: roles of families and health professionals

We examined families' end-of-life decision making and their interactions with health professionals. Twenty-eight family members of institutionalized dementia patients participated in four focus groups. We found that participating family members were not well prepared for their decision-making roles, and that they: 1) experienced substantial burdens and loss in caring for institutionalized elders; 2) had limited understanding of the natural progression of dementing conditions; 3) were uncomfortable in setting goals for their relatives' end-of-life care; 4) had little experience with death, and were ambivalent about the anticipated death of their relative; and (5) reported that they had little substantive communication with health professionals regarding end-of-life care planning. We concluded that many of the needs of such families could be addressed through improved application of the principles of advance care planning, including regular structured discussions, involvement of surrogate decision-makers, and anticipation of clinical decisions. Health professionals should take the lead in 'normalizing' the discussion of death.     

A new quantitative method for assessing sleepiness: The alpha attenuation test

Abstract

Sleepiness interferes with the ability of night-workers and shiftworkers to safely and effectively perform their jobs, and has been increasingly recognized as a major cause of industrial and transportation accidents. Current methods for the assessment of physiological sleepiness levels, such as the Multiple Sleep Latency Test (MSLT) have several limitations and are particularly impractical in field or occupational studies. In this study, the effectiveness of the Alpha Attenuation Test (AAT) for the quantification of sleepiness has been evaluated and compared to the MSLT during a 40-h sleep deprivation protocol. The AAT, a 12-min eye closed/open protocol, is a quantitative method based on the fact that EEG alpha (8-12 Hz) activity tends to increase with eyes open as individuals get sleepier, while it decreases with eyes closed. In this validation study, the AAT proved to be a sensitive measure of sleepiness induced by sleep deprivation, and it also correlated well with the MSLT. Relative to the MSLT, the AAT has the advantages of being objective, minimally intrusive, and more practical especially in industrial or field studies.     

Cultural influences on parental bereavement in Chinese families

The purpose of this study was to explore the bereavement experiences of parents who had experienced the death of a child in Chinese families. In-depth interviews were conducted with 10 bereaved parents in Macau, China. Narrative accounts of Chinese parents' experience in the loss of a child were explored to understand how their connection to the deceased child and their worldview were influenced by cultural beliefs and values. Study themes related to parental connections with the deceased child included the use of object linking, memorializing acts, and avoidance of traditional funeral processes, with clear patterns of Chinese cultural influence. Additionally, themes related to impacts on parental worldview included use of the concept of fate as a rationale for child loss and influences on religious orientation. The influence of cultural beliefs and background on Chinese parents as they deal with the issue of a child's death was apparent. Further research is needed and will benefit our understanding of parental bereavement in Chinese families.     

The cross-cultural adjustment process of expatriate families in a multinational organization: a family system theory perspective

This case study examined the relationship between the family flexibility of expatriates in a multinational corporation and their cross-cultural adjustment, as well as the stressors experienced by the expatriate, spouse, and children during the international transition. Family flexibility was negatively correlated with cross-cultural adjustment as perceived by the participating expatriates. All five cross-cultural adjustment dimensions (cultural, psychological, organizational, personal and relational) had a statistically significant relationship with family flexibility. Expatriate families identified cultural, relational, and psychological stressors as having the greatest impact on their cross-cultural adjustment. The components of family flexibility (roles, rules, assertiveness and leadership) played a key role in the cross-cultural adjustment of the expatriate, spouse and children. These findings provide insights to organizations and their human resource development professionals as well as to expatriates and their families on how family flexibility impacts cross-cultural adjustment – insights that could lead to the development of appropriate support and development mechanisms.     

Multi-objective scheduling of two-job families on a single machine

This paper presents a preliminary analysis of the typical scheduling environment in semiconductor manufacturing involving multiple job families, and where more than one objective such as cycle time, machine utilization and the due-date accuracy needs to be simultaneously considered. In this study, the NP-hard problem of scheduling N independent jobs on a single testing machine with due dates and sequence-dependent setup times is addressed, where the multiple objectives are to minimize average cycle time, to minimize average tardiness, and to maximize machine utilization. A Pareto optimal solution, which is not inferior to any other feasible solutions in terms of all objectives, is generated combining the analytically optimal and conjunctive simulated scheduling approach. First, the machine-scheduling problem is modeled using the discrete event simulation approach and the problem is divided into simulation clock based lot selection sub-problems. Then, a Pareto optimal lot is selected using the compromise programming technique for multiobjective optimization at each decision instant in simulated time. With the help of a broad experimental design, this developed solution is then compared with common heuristic-dispatching rules such as SPT and EDD, which show better results for all the objectives over a wide range of problems. The developed scheduling method shows approximately 16.7% reduction in average cycle time, 25.6% reduction in average tardiness, and 21.6% improvement in machine utilization over the common dispatching rules, SPT and EDD.     

固定分区下随机需求IRP问题最优策略及算法

随机需求库存-路径问题(stochastic demand inventory routing problem,SDIRP)是典型的NP难题,考虑随机需求环境下供应链中库存与配送问题的协调优化,是实施供应商管理库存策略的关键所在.文章的研究基于固定分区策略(fixed partition policy,FPP),在FPP下客户被分为若干个服务区域,在同一区域中的所有客户均被同时配送.根据分区策略对配送以及库存成本的影响提出了基于修正C-W节约算法的客户分区算法,证明了各区域的最优库存策略为(s,S)形式,分区内各客户的库存策略为order-up-to形式,进而设计了求解FPP下SDIRP最优策略的算法.最后,通过数值算例验证了该算法的有效性以及FPP的适用性.     

A new method for order release

A new method for determining when to release jobs into a probabilistic manufacturing line is described. This new heuristic releases jobs only if their predicted waiting times are sufficiently estimated using simulation. Moreover, we use simulation to examine the performance of this heuristic and others CONWIP, Starvation Avoidance for a manufacturing flow line with exponential machine processing, failure, and repair times. The reasons why it is appropriate to compare order release mechanisms using tradeoff curves of lead time versus customer service are described. The simulation experiments show that the new 'waiting time heuristic' is superior to other order release mechanisms in situations where low lead time is required. small. Waiting times are     

A method for exploring the future

This paper describes a method for exploring future policy options. The procedures for choosing the range of options and constructing the future scenarios are described with special emphasis on policy implications. The advantages and limitations of this approach are discussed. The construction of scenarios is illustrated by describing three energy policy options for the U.K. The detailed analysis of these energy options, including their political and resource implications, will be described in a later paper.