Finding a Noncrossing Steiner Forest in Plane Graphs Under a 2-Face Condition

Let G = (V,E) be a plane graph with nonnegative edge weights, and let be a family of k vertex sets , called nets. Then a noncrossing Steiner forest for in G is a set of k trees in G such that each tree connects all vertices, called terminals, in net N _i, any two trees in do not cross each other, and the sum of edge weights of all trees is minimum. In this paper we give an algorithm to find a noncrossing Steiner forest in a plane graph G for the case where all terminals in nets lie on any two of the face boundaries of G. The algorithm takes time if G has n vertices and each net contains a bounded number of terminals.     

Population biology of the broad-horned flour beetle,Gnathocerus cornutus (F.) II. Crowding effects of larvae on their survival and development

Summary Crowding effects of larvae on survival and development were examined for the broad-horned flour beetle,Gnathocerus cornutus (F.). The larvae matured about 3 weeks after hatching regardless of their densities, but pupation was severely hindered by crowding. There existed an upper limit for the number of the pupae produced and its mechanism was studied by a statistical analysis of the distribution patterns of pupal cells and the experiment in which glass tubes were artificially supplied in addition as pupation site. These studies show thatG. cornutus larvae have a habit to construct cells for pupation and this habit leads to a contest competition for pupation site at high densities. The significance of the contest competition for population regulation was discussed comparing the results onTribolium confusum Jacqueline duVal.     

The approximation of an unbiased test with a small level for the bioequivalence problem

In the bioequivalence problem. Brown. Hwang and Munk (1997) constructed an unbiased level a test and other tests which are uniformly more powerful than the two one-sided tests procedures when a iscomparatively larger. In this paper, for a small level, an unbiased test is shown to be approxirnately constructeQ lor tnis prooiem oy using tneir Metnog. ine numerical construction is also given.     

移动商务中面向客户细分的KSP混合聚类算法

数据挖掘技术中的聚类算法是解决客户细分问题的重要算法之一。为解决传统聚类算法在客户细分问题中分类精度较低、收敛速度较慢的问题,着重对比分析传统聚类算法中K-m eans、自组织映射网络和粒子群3种算法的不足,提出融合3种算法优点的混合型聚类算法,该算法利用K-m eans和自组织映射网络对初始聚类中心进行优化,结合粒子群优化和K-m eans优化聚类迭代过程,并在迭代优化过程中设计避免算法因早熟而停滞的机制。针对移动电子商务环境下的餐饮业客户细分问题,建立移动餐饮业客户细分模型,并利用混合型聚类算法、K-m eans、层级自组织映射网络和基于粒子群的K-m eans等4种算法对实际案例进行对比分析。研究结果表明,混合型聚类算法的聚类精度分别比其他3种算法高,同时还具有最快的收敛性能,更适用于客户细分问题。     

Average-case competitive analyses for one-way trading

Consider a trader who exchanges one dollar into yen and assume that the exchange rate fluctuates within the interval [m,M]. The game ends without advance notice, then the trader is forced to exchange all the remaining dollars at the minimum rate m. El-Yaniv et al. presented the optimal worst-case threat-based strategy for this game (El-Yaniv et al. 2001). In this paper, under the assumption that the distribution of the maximum exchange rate is known, we provide average-case analyses using all the reasonable optimization measures and derive different optimal strategies for each of them. Remarkable differences in behavior are as follows: Unlike other strategies, the average-case threat-based strategy that minimizes E[OPT/ALG] exchanges little by little. The maximization of E[ALG/OPT] and the minimization of E[OPT]/E[ALG] lead to similar strategies in that both exchange all at once. However, their timing is different. We also prove minimax theorems with respect to each objective function.     

Synchronic and diachronic variation in the use of spatial frames of reference: An analysis of Japanese route instruction

By focusing on everyday use of spatial ‘frames of reference’ (FOR) in route instruction, we propose some possible explanations for the seemingly contradictory trends observed in FOR‐based and deixis‐based spatial expressions in Japanese. We examined the data obtained in a series of longitudinal surveys conducted in Japan over 50 years (1953, 1972 and 2008). Our GoldVarb analysis confirmed what is called a ‘retrograde’ lifespan change. This indicates that, first, synchronically, the preference for External FOR (that is, based on North‐South‐East‐West) increases as community members grow older. This means they shift toward the local norm through ‘age‐grading’. Secondly, diachronically, the preference for Internal FOR (based on Right‐Left‐Front‐Back) has gradually increased over the past century. There is, therefore, a ‘generational change’ motivated by the linguistic marketplace. In contrast, as a community‐wide preference for Internal FOR expressions prevails, there is an accompanying gradual decrease in the use of deictic expressions such as ‘here/there/over there’. This indicates a partially complementary relationship between deixis and Internal FOR.     

Recovering Heritage and Homeland: Ethnic Revival Among Fourth‐Generation Japanese Americans

In recent years, fourth‐generation Japanese American youth have been attempting to recover their ethnic heritage and reconnect with their ancestral homeland. This ethnic revival is a response to their continued racialization as “Japanese,” which has caused them to become concerned about their overassimilation to American society in an era of multiculturalism where cultural heritage and homeland have come to be positively valued. As a result, they are studying Japanese, majoring in Asian studies, living in Japan as college exchange students, and participating in Japanese taiko drum ensembles in local ethnic communities. Although this return to ethnic roots is a more serious commitment than the symbolic ethnicity observed among white ethnics in the past, it indicates that ethnicity remains involuntary for racial minorities, even after four generations. The case of later‐generation Japanese Americans demonstrates that cultural assimilation does not preclude the continuation and active production of ethnic difference.     

Reproductive strategy of insects as adaptation to temporally varying environments

Summary Diversity of oviposition curve observed in 125 insects was analysed using the ratio of the length of period for development to that for reproduction. On the basis of this empirical data, two extreme reproductive patterns were selected: prolonged reproduction with early maturity and concentrated reproduction with late maturity. Population growth of the species with each reproductive pattern was calculated usingLeslie Matrix under some simulated fluctuating environments where the length of time during which the environments change is short compared with the time required to stabilize age structure. These simulation studies show that there is an optimal ratio of the length of period for development to that for reproduction in achieving high population densities and this ratio varies depending on the favorableness of environment for reproductive success: as the environmental favorableness decreases, the optimal ratio becomes larger.     

Defining and organizing self-advocate centered groups: implications of survey research on self-advocacy groups in Japan

Ideally group members who have intellectual disabilities should have power in their self-advocacy groups, leading to groups that can be considered 'self-advocate centered.' Currently, not all self-advocacy groups can be considered self-advocate centered because group advisors have an overwhelming influence on group decisions. This article assumes that establishing self-advocacy groups in which members truly control the agenda and make key decisions is one of the most effective methods to empower people with intellectual disabilities. This study identifies factors useful in identifying 'self-advocate centered' groups, and especially focuses on the relationship between self-advocates and advisors. It is based on a quantitative research project conducted in Japan. According to the results of the research, though relational transformation between self-advocates and advisors was commonly seen in many self-advocacy groups, conflicts between them were scarcely observed. The meaning of relational transformation without conflicts is considered, along with the concepts of independence and interdependence.