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This paper proposes an efficient direct yaw moment control (DYC) capable of minimising tyre slip power loss on contact patches for a four-independent wheel drive vehicle. Simulations identified a s...

There is an increasing demand for sub-meter vehicle localization for advanced safety and autonomous systems. Fault detection and isolation (FDI) for sensor systems, such as camera, LIDAR, GNSS, and V2X has been a challenge because their performances are significantly affected by weather, geographical changes, and even spoofing. In this paper, a sensor FDI using Student’s t-distribution based adaptive unscented Kalman filter is presented. The proposed filter evaluate each sensor by Hotelling’s T2 test utilizing the predicted sensor output and its covariance. This method can assess the correlation between data that is generated within the same sensor, for accurate fault detection. In addition, measurement noise is adaptively updated by identifying both the covariance and the degree of freedom of the outlier robust Student’s t-distribution. The robustness and accuracy of the localization and measurement noise estimation is confirmed through simulation and an experiment on a highway scenario. Furthermore, the result also shows that the precise FDI can be achieved without any prior information regarding sensor measurement noise. The proposed algorithm enhances the reliability of future position based systems such as autonomous control or V2V safety brake.

Driving force distribution control is one of the characteristic performance aspects of in-wheel motor vehicles and various methods have been developed to control direct yaw moment while turning. However, while these controls significantly enhance vehicle dynamic performance, the additional power required to control vehicle motion still remains to be clarified. This paper constructed new formulae of the mechanism by which direct yaw moment alters the cornering resistance and mechanical power of all wheels based on a simple bicycle model, including the electric loss of the motors and the inverters. These formulation results were validated by an actual test vehicle equipped with in-wheel motors in steady-state turning. The validated theory was also applied to a comparison of several different driving force distribution mechanisms from the standpoint of innate mechanical power.

In the structural design of mechanical products, natural frequencies must be controlled to reduce noise and vibration. In particular, the stiffness of the joints which assemble the structural components affects the natural frequencies. Therefore, it is important to predict the influence of joint stiffness on natural frequencies. Generally, these effects are determined by iterative finite element analyses of assembled structural models. Because this results in high computational costs, the sensitivity of natural frequencies to joint stiffness should be determined by a different approach to make the structural design process more efficient. Therefore, this paper proposes the use of reflection and transmission coefficients of elastic joints to predict the dependency of natural frequencies on joint stiffness. First, we formulate the reflection and transmission coefficients of joint stiffness, and then organize the coefficients using a ray tracing method. These formulations enable us to discuss the mechanisms which determine the natural frequency of a structure based on a wave approach using the phase-closure principle. Therefore, by applying the phase-closure principle to the frame structure, we investigate the formation of bending modes, which suggests that the effects of joint stiffness on natural frequencies correspond to the dependence of the reflection and transmission coefficients on joint stiffness. Therefore, these coefficients are useful indicators for estimating the influence of joint stiffness.

Fecal DNA-based 16S ribosomal RNA (rRNA) gene sequencing using next-generation sequencers allows us to understand the dynamic gut microbiome adaptation of animals to their specific habitats. Conventional techniques of fecal microbiome analysis have been developed within the broad contexts defined by human biology; hence, many of these techniques are not immediately applicable to wild nonhuman primates. In order to establish a standard experimental protocol for the analysis of the gut microbiomes of wild animals, we selected the Japanese macaques (Macaca fuscata yakui) on Yakushima Island. We tested different protocols for each stage of fecal sample processing: storage, DNA extraction, and choice of the sequencing region in the bacterial 16S rRNA gene. We also analyzed the gut microbiome of captive Japanese macaques as the control. The comparison of samples obtained from identical macaques but subjected to different protocols showed that the tested storage methods (RNAlater and lysis buffer) produced effectively the same composition of bacterial operational taxonomic units (OTUs) as the standard frozen storage method, although the relative abundance of each OTU was quantitatively affected. Taxonomic assignment of the detected bacterial groups was also significantly affected by the region being sequenced, indicating that sequencing regions and the corresponding polymerase chain reaction (PCR) primer pairs for the 16S rRNA gene should be carefully selected. This study improves the current standard methods for microbiome analysis in wild nonhuman primates. Japanese macaques were shown to be a suitable model for understanding microbiome adaptation to various environments.

A well-known behavioural model for group aggregation is that an individual depends on a few neighbouring individuals to adjust its movement, such as departure (repulsion) from and approach (attraction) to neighbours. However, an individual may rely not only on a few closest neighbours, but also on more distant individuals, in a group of stable membership. We measured temporal changes in the local density of individuals around a focal individual and changes in distance to other focal individuals in a group of wild Japanese macaques to determine whether the macaques depended only on a few neighbours or also on more distant individuals for adjustments in cohesiveness. We used simultaneous focal animal sampling, with two observers recording the individuals' locations using a global positioning system (GPS), over three seasons. Numbers of individuals within 20 m from an animal tended to increase after 10 min when there were a small number of individuals around the animal. However, the number tended to decrease when there was a larger number of individuals. It remained similar when there were an intermediate number of individuals. The two focal animals tended to separate after 10 min when the interindividual distance was short. However, they tended to move closer when far apart. They remained a similar distance apart when they were at an intermediate distance. Contact calls, which are suggested to function as locating group members and keeping cohesiveness, were emitted more frequently when the distance between the two focal animals was very large in two seasons. However, the rate of contact calls was not influenced by the number of individuals within 20 m from an animal. These results suggest that individual Japanese macaques do not only rely on a few closest neighbours, but also rely on more distant group members. Japanese macaques may know the general whereabouts of the whole group, and when they stay at the periphery of the group, they may emit contact calls frequently and move towards the central zone so as not to become separated from the group.

The spatial cohesiveness of a group is an important element that characterizes the social structure of group-living species. Moreover, remaining cohesive is crucial if individuals are to coordinate their activities and reach collective decisions. We measured interindividual spacing in a group of wild Japanese macaques (Macaca fuscata) to assess the spatial cohesiveness of a social group quantitatively. We used simultaneous focal animal sampling, with 2 observers recording individuals’ locations with a global positioning system (GPS) during 3 seasons. Interindividual distances differed among seasons; they were short in autumn (mean ± SD: 25.6 ± 20.1 m), intermediate in winter (mean ± SD: 46.3 ± 35.7 m), and long in summer (mean ± SD: 62.3 ± 47.1 m). Measurements taken in summer revealed extremely wide spacing (maximum: 1225 m), suggesting subgrouping. Distances also varied with activity during each season; they were short during resting and grooming, intermediate during foraging, and long during moving. Group cohesion was also influenced by food distribution. More group members were ≤20 m of the focal individual during foraging on clumped food than foraging on scattered food in each season, and the group foraged on clumped food most frequently in autumn. Individuals were also likely to aggregate at resting/grooming sites and clumped food patches and to disperse when moving within a day. These results demonstrate that Japanese macaques show considerable variation in spatial cohesiveness both within short time periods, e.g., 1 d, and among seasons, and that they adjust group cohesiveness flexibly depending on the food conditions and foraging tactics.

Tripod constant velocity joints are used in the driveshafts of front wheel drive vehicles. Thrust force generated by this joint causes lateral vibration in these vehicles. This paper surveys some methods for reducing the thrust force based on the mechanisms inducing the thrust force, focusing on a method that creates dual contact between a roller and groove. This method has the advantage of requiring only a few design modifications, but its thrust force reduction mechanism has yet to be clarified. Therefore, a theory was constructed to describe the induction of thrust force by this method through the application of sliding velocities generated between the roller and dual contact groove. Subsequently, the effect of the thrust force reduction was investigated. This paper also describes the appropriateness of this theory. It was validated by comparing theoretical results with computational results based on a multibody dynamics approach and with experimental results of a prototype joint equipped with the dual contact grooves.

Tripod constant velocity joints are used in the driveshaft of front wheel drive vehicles. Thrust force generated by this joint causes lateral vibration in these vehicles. To determine the mechanisms inducing the thrust force, a detailed model is constructed based on a multibody dynamics approach. Although the joint is equipped with three rollers and grooves, this model consists of the principal parts for one roller and groove in order to precisely analyze frictional phenomena occurring between the roller and the groove. These principal parts are defined as rigid bodies and are connected by force elements of contact and friction. The appropriateness of this model is verified by comparing computational and experimental results and it is clarified that the principal factors inducing the thrust force are three kinds of sliding friction force at the point of contact between the roller and the groove. This paper also describes the reason why the third rotating order component of the thrust force is induced by one roller and groove.

A tripod constant velocity joint is used in the driveshaft of front wheel drive vehicles. Thrust force generated by this joint causes lateral vibration in these vehicles. To analyze the thrust force, a detailed model is constructed based on a multibody dynamics approach. This model includes all principal parts of the joint defined as rigid bodies and all force elements of contact and friction acting among these parts. This model utilizes a new contact modeling method of needle roller bearings for more precise and faster computation. By comparing computational and experimental results, the appropriateness of this model is verified and the principal factors inducing the second and third rotating order components of the thrust force are clarified. This paper also describes the influence of skewed needle rollers on the thrust force and evaluates the contribution of friction forces at each contact region to the thrust force.

A major function of contact calls in nonhuman primates is to maintain spatial cohesion among individuals in a group. The risks of spatial/visual separation from the group are likely to affect auditory contact behavior, in particular by increasing the call rate. We tested whether the risk of separation influences coo call emission by investigating the variation in call rate among behavioral contexts in two wild populations of Japanese macaques (Macaca fuscata). We focused on caller activity and the degree of visibility within the habitat as primary potential factors mediating call rate. We first estimated the habitat visibility of the two research sites at Yakushima Island (YK) and Kinkazan Island (KZ), Japan. The habitat visibility of YK was significantly more restricted than that of KZ. We then compared the call rate of 20 adult and 12 juvenile female macaques between the two wild populations to examine the potential effects of environmental differences. Both populations had a lower call rate during grooming than during feeding and moving, which are behaviors associated to higher interindividual distances. The call rate of YK adult females was significantly greater than that of both juveniles and KZ adult females, independently of activity. The call rate increased as macaques matured in the YK population, but not in the KZ population, suggesting that different developmental processes involved in contact calling of the two populations. Our findings suggest that separation risk influences call rate, and also imply a possibility of social influence that social structure change effects on the call rates. Am. J. Primatol. 70:1055–1063, 2008. © 2008 Wiley-Liss, Inc.

Acoustic features of coo calls in Japanese macaques (Macaca fuscata) show large and graded variation. To explore the relevance of acoustic variation in coo calls, I examined whether acoustic features differed by the caller's activity and proximity to group members. The subjects were five adult females from a wild, habituated group of Japanese macaques consisting of 23 individuals. Coo calls from the five females were recorded with their activity and proximity to group members. Acoustic features of 280 calls were measured with a sound spectrograph. Some of the acoustic variables differed by proximity but not by activity. The callers produced coo calls with larger frequency modulation and longer duration when they were far from group members compared to when they were near another member. The results suggest that Japanese macaques produce calls with more detectable and locatable features depending on the proximity to group members. Am. J. Primatol. 69:1412–1424, 2007. © 2007 Wiley-Liss, Inc.

We examined acoustic individuality in wild agile gibbon Hylobates agilis agilis and determined the acoustic variables that contribute to individual discrimination using multivariate analyses. We recorded 125 female-specific songs (great calls) from six groups in west Sumatra and measured 58 acoustic variables for each great call. We performed principal component analysis to summarize the 58 variables into six acoustic principal components (PCs). Generally, each PC corresponded to a part of the great call. Significant individual differences were found across six individual gibbons in each of the six PCs. Moreover, strong acoustic individuality was found in the introductory and climax parts of the great call. In contrast, the terminal part contributed little to individual identification. Discriminant analysis showed that these PCs contributed to individual discrimination with high repeatability. Although we cannot conclude that agile gibbon use these acoustic components for individual discrimination, they are potential candidates for individual recognition. Am. J. Primatol. 69:777–790, 2007. © 2007 Wiley-Liss, Inc.

Japanese macaques (Macaca fuscata) exchange coo calls with group members to maintain contact. I examined the relationship between the distance between group members and (1) the latency of vocal responses to spontaneous calls, and (2) the latency of spontaneous call repetition in the absence of vocal responses. After a subject monkey's spontaneous call, the latency of vocal response by another group member was longer when the subject was farther from the group members than when the subject was near the group members. Furthermore, subject repeated calls with longer intervals in the absence of vocal response, which suggests that they wait longer for the vocal responses of other group members when the expected response latency is longer. These results reveal that Japanese macaques flexibly alter the timing of their calls based on others' vocal responses.

Seasonal variation in fecal testosterone levels in free-ranging male Japanese macaques (Macaca fuscata) was examined with reference to their dominance rank and age class. Six adult (≥7 years old, three higher-ranking and three lower-ranking) and four adolescent (5–6 years old, two higher-ranking and two lower-ranking) males were selected as target animals. Fecal samples of these males were collected during the first 3–5 days of each month and analyzed by the method developed by Barrett et al. [Primates 43:29–39, 2002b]. Testosterone levels varied significantly across the 12 months, and were highest in the early and middle parts of the mating season (i.e., October and November). Higher-ranking adult males displayed a peak testosterone level in October, whereas lower-ranking adults had no clear peak in the mating season. Such a difference in testosterone peaks in males could provide higher-ranking males more opportunities to fertilize females at first ovulation in the mating season than lower-ranking males. Am. J. Primatol. 69:603–610, 2007.© 2007 Wiley-Liss, Inc.

Three levels of hamadryas social structure--the one male unit (OMU), the band, and the troop--have been observed at all sites studied, but a fourth--the clan--has been observed at only one site, Erer-Gota, Ethiopia, during a longitudinal check of the dispersion of identified individuals. The clan is important since it appears to provide the basis for male philopatry, although comparative data is needed from other sites to confirm this. We studied a huge commensal group of hamadryas baboons (over 600 animals) in Saudi Arabia. We put ear tags on baboons between 1998 and 2004 and analyzed social structure, relying on the interactions of these tagged animals by focusing especially on their dispersal patterns from OMUs. OMU membership tended to be looser than that of the Ethiopian hamadryas. Females tended to shift between OMUs on an individual basis in our study group, whereas the collapse of an OMU was a major occasion of adult female transfer in Ethiopia. We found neither stable bands (a "band" in our study group was defined as a regional assemblage of OMUs) nor clans that lasted for several years. Some OMUs moved and transferred into neighboring areas over both the short and long term. Further, some post-adolescent males appeared to move out of the study area. The ratio of adult females in an OMU in our study group was larger than for any other documented study site, and this may be the reason for enhanced female transfer between OMUs. A large proportion of the adolescent females showed no clear membership to OMUs, and no "initial units" (commonly observed in Ethiopia) were discernible. The ease with which young males acquired adult females at the study site must have disrupted the formation of a clan, a "male-bonded society."

Japanese macaques, Macaca fuscata, frequently utter coo calls to maintain vocal contact. Cross-sectional and longitudinal comparisons were conducted on the acoustic features of coo vocalizations of two groups of M. fuscata, Yakushima and Ohirayama groups, to explore the possibility of vocal plasticity. These two groups derive from the same local population but have been separated for more than 34 yr. The Yakushima group is non-provisioned, while the Ohirayama group is provisioned. Initially, coo calls in the two groups were compared cross-sectionally in females ranging from 0 to 18 yr. Mean values of the four variables studied (start, end, maximum, and minimum frequencies) were consistently lower in all age groups of the Ohirayama individuals compared with the Yakushima individuals. Secondly, longitudinal comparisons were conducted on individuals in the 1-4 yr after birth. Mean values of the five frequency variables studied (start, end, maximum, minimum and average frequencies) were again consistently lower in all age groups of Ohirayama compared with Yakushima individuals, although mean values of both groups gradually declined with an increase in age. Inter-group differences were significant at all ages in minimum frequency and at the first, second and third years in start frequency. Longitudinal comparisons of individuals aged 4-11 mo were also conducted. Regarding the four variables that differed between the two groups in the cross-sectional study, the mean values of minimum and start frequency did not differ significantly between the two groups at 4-5 mo, but were significantly lower in Ohirayama individuals aged 7-8 and 9-11 mo. Although provisioning may have had an effect on the weight difference between the groups, and consequently on vocalization frequency, these results suggest that the inter-group differences in coo call features form approximately 6-7 mo after birth as a result of vocal plasticity.

Recently, the acoustic features of coo calls were reported to differ between two populations of Japanese macaques (Macaca fuscata yakui), namely the Ohirayama and Yakushima populations. We hypothesized that this difference may arise through differences in the acoustic environments of the two habitats, and measured the degrees of transmission of pure tones (250-8000 Hz) and the coo calls of the two populations in each habitat. In the Ohirayama habitat, lower frequencies were transmitted more efficiently, and the low-pitched coo calls of the Ohirayama population showed significantly better transmission than the high-pitched calls of the Yakushima population. In the Yakushima habitat, the degrees of transmission of the calls of the two populations did not differ significantly. Therefore, the calls of the Ohirayama population possess acoustic features that allow better transmission in their own habitat, suggesting that the habitat acoustics may be a factor contributing to the population difference between the calls.

プロジェクト・アプローチは，幼児教育を含む初等教育におけるプロジェクト学習の指導論である。このアプローチは，子どもの知的，社会的な発達に果たすプロジェクトワークの意義を強調し，カリキュラムへの編入を求めている。またプロジェクトワークの実際に取材し，そこに典型的にみられる子どもの活動の局面や内容をカテゴライズして，指導のためのモデルを実際に示している。本稿では，このアプローチが示しているプロジェクトモデルの妥当性について考察した。そのために，①プロジェクト・アプローチの概要とモデルの紹介，②いま世界的に注目を集めているレッジョ・エミリアにおけるプロジェクト学習の具体的な記述，③レッジョ・エミリアの実践のプロジェクト・アプローチに対する影響の吟味，④プロジェクト学習をめぐる双方の見解の比較とモデルの検討を行った。そしてプロジェクト・アプローチのモデルはプログラム化のリスクを含むことを指摘し，新たなプロジェクトモデルのイメージを示した。, The Project Approach is a guiding theory of the project teaching in the primary education including an early childhood. The Project Approach emphasizes on the importance of children's projectwork for their intellectual and social development that has been suggesting incorporating into the primary education curriculum. In addition the Project Approach proposes the pragmatic teaching model based on children' typical activity types and phases. In this paper, the validity of the project model, which was proposed by the Project Approach, was examined theoretically as well as practically. In order to do the examination of the validation of the models, the following four areas were included: (1) comprehensively introducing the Project Approach and its project model, (2) describing the application of the Project Approach to the project learning practice of Reggio Emilia, which currently gets international attention among the early childhood education field, (3) examining Reggio Emilia's effects on the Project Approach, and (4) examining the difference of understanding of projectwork between the Project Approach and Reggio Emilia. Results suggested disadvantages of the practical programming of the Project Approach without examining the validity. The new model image was suggested.

The mass mortality of wild Japanese macaques (Macaca fuscata Blyth) was observed in a warm temperate forest of Yakushima, southern Japan. Demographic changes of eight troops between August 1998 and August 1999 were studied and 56% of macaques disappeared from the five intensively studied troops. Mortality varied among troops: two troops became extinct, while another troop did not decrease in size. The rate of mortality of the other troops was between 33 and 80%. The variation in mortality among the troops was either the outcome of local concentrations of mortality or of intertroop competition. The rate of mortality decreased with increasing distance from the two extinct troops and with increasing troop size; these two factors could not be separated statistically. The direct cause of death was diagnosed as pneumonia for four out of five fresh carcasses. The fleshy fruit production in autumn 1998 was the lowest in 14 years, and macaques had relied on leaves earlier than in usual years. It was exceptionally hot and dry in the summer of 1998. The exceptionally poor fruit production and hot summer of this year, with the resulting shortage of high-quality foods, was consistent with the scenario that mass mortality was due to the poor nutritional conditions. However, the possibility that epidemics caused the mass mortality cannot be ruled out. Our findings proved that primates in a seemingly stable habitat experience fluctuations in demographic parameters under natural conditions.

In this study we investigated the reproductive characteristics of wild female Japanese macaques (Macaca fuscata fuscata) in 2 nonconsecutive years using noninvasive methods to monitor physiological events. We detected ovulation dates and ascertained conceptions from fecal hormone profiles. First ovulations occurred from middle October to early November in 1997, and from middle to late November in 1999. Most females conceived during their first ovarian cycle. On average, postconception bleeding occurred 18.4 days after ovulation, and menstruation occurred 13.7 days after ovulation. The average gestation length was 176.3 days. The average degree of facial redness and the percentage of females that copulated synchronously changed across the ovarian cycle and peaked in the periovulatory period. Although prolonged periods of postconception copulation have been reported in previous studies, they did not occur in this study, which suggests that such behavior may not be a species-typical characteristic. Female fertility varied between the 2 years. The copulation rates of females with no infant

The population density of Japanese sika deer (Cervus nippon yakushimae Kuroda and Okada) in an evergreen broad-leaved forest in Yakushima, southern Japan, was surveyed over 4 years from 1998 to 2001. Two approximately 50 ha study sites, Hanyama and Kawahara, were established with a total of 4 km of census trails at each site. The estimated densities of sika deer at the two sites were 43–70 deer km−2 at Hanyama and 63–78 deer km−2 at Kawahara, although these values might be underestimates. The adult sex ratio (number of adult males : number of adult females) ranged from 0.6 to 1.0 at Hanyama, and from 0.4 to 0.9 at Kawahara. Mean group size was 1.9 deer (male group, 1.5 deer; female group, 1.6 deer; mixed group, 3.6 deer). The population density of sika deer was relatively high compared to other sites in Japan, with the exception of very small (

合衆国では1910年頃からモンテッソーリシステムが熱心に紹介され，注目を集めた。小稿では，この時期になされたキルパトリックのモンテッソーリ批判（1913＆1914）の内容を，後の彼の70ロジュクト法の提起（1918）にどのような意味を与えたかという視点から検討した。この批判によって彼は進歩主義の立場から当時の合衆国の幼稚園運動を擁護しようとしたが，同時に批判の対象であるモンテッソーリの思想や実践にヒントを得ながら，彼自身がそれまで教師として培ってきた発想に教育学的な表現を与えている。その内答には，すでにプロジェクト法の理論的な萌芽も見出される。, In the U.S., after around 1910, the Montessori System was zealously introduced and was focused the attention. Kilpatrick's severe criticism of this system appeared in 1913 and 1914. His criticism is generally sited as a strong reason for decline of the Montessori Movement today. This paper examines his criticism from the viewpoint of what effect it had for his project method theory, proposed in 1918. By the criticism, Kilpatrick, as a progressive thinker, intended to defend the Kindergarten Movement in the U.S. in those days from the Montessori System. He had just become a scholar of education at Teachers College, could give pedagogical expression to his way of thinking that had already been gained thorough his own experience as a school teacher. He was much influenced by Dewey and Thorndike, and got ideas through criticism of the Montessori's educational thought and practice. We can find several original conceptions of the project method theory in his criticism.

We observed three cases of troop extinction and two cases of female fusion in the wild population of Japanese macaques on Yakushima Island, Japan. Troops P and T decreased in size relatively slowly over a few years until each troop consisted of only three monkeys. Several months later, the remaining adult female of P merged with the adjacent troop S, followed by the remaining female of T. S subsequently also decreased in size and disappeared about 2 years later. In the early stage of troop decline, the mortality rate of adult females was as low as in a growing troop, but the birthrate was quite low. In the late stage of troop decline, the mortality rate increased and the birthrate remained low. An important factor leading to troop extinction may be an increase in population density and the resulting increase in intergroup competition. During the period when P and T declined and ceased to exist, the range of the adopted troop shifted to cover their previous ranges. In the fused troop, there was no severe aggression directed towards the immigrant females or harassment from residents of the adopted troop and there was affiliative social interaction between the immigrant females and resident members. These results agree with previous reports on female fusion: it occurs when the shrinking group consists of one or no adult member, and the immigrant females are not at a severe disadvantage in their adoptive group. A possible benefit for immigrant females is to avoid disadvantage of one-adult group in conflict with conspecifics. A possible cost for immigrant females is transfer to the other troop or to unfamiliar area or both. The cost to transfer to another group may not be high because the members of the adoptive troop are relatively tolerant to immigrants. The cost to transfer to unfamiliar range may be minimized by immigration to the troop whose range shifted to the immigrants' former range.