Game logic and its applications I

This paper provides a logic framework for investigations of game theoretical problems. We adopt an infinitary extension of classical predicate logic as the base logic of the framework. The reason for an infinitary extension is to express the common knowledge concept explicitly. Depending upon the choice of axioms on the knowledge operators, there is a hierarchy of logics. The limit case is an infinitary predicate extension of modal propositional logic KD4, and is of special interest in applications. In Part I, we develop the basic framework, and show some applications: an epistemic axiomatization of Nash equilibrium and formal undecidability on the playability of a game. To show the formal undecidability, we use a term existence theorem, which will be proved in Part II.The authors thank Hiroakira Ono for helpful discussions and encouragements from the early stage of this research project, and Philippe Mongin, Mitio Takano and a referee of this journal for comments on earlier versions of this paper. The first and second authors are partially supported, respectively, by Tokyo Center of Economic Research and Grant-in-Aids for Scientific Research 04640215, Ministry of Education, Science and Culture.Presented by H. Ono     

Spontaneous blinks as a criterion of visual fatigue during prolonged work on visual display terminals

Visual fatigue caused by prolonged work viewing a Visual Display Terminals (VDT) and of work reading a hard-copy were assessed by electromyogram (EMG) waveform and electrooculogram (EOG) waveform in spontaneous blinks as objective criteria, and by questionnaire of subjective feeling, and by task performance. The duration and the amplitude of the EMG of the orbicularis ocular muscle on the right side and the EOG of the vertical direction to the eyelid were measured for 10 subjects who participated in a figure task consisting of the addition of single-digit numbers on a VDT work or a work with a hard-copy. The mean values of the duration and the amplitude of the EMG and the EOG were evaluated by the averaging of 10 waveforms of the spontaneous blinks for all subjects. The time lag from the EMG to the EOG in the process of the generation of spontaneous blinks was also analyzed. These five parameters were evaluated during the work time. The mean values for the duration of the EMG increased gradually during the work time, but the amplitude did not show significant difference between the prework and a work time. There was no significant change of the duration of the EOG, but the mean amplitude of the EOG decreased as the work time progressed, and the time lag significantly extended. The blinks frequency increased relatively when using a VDT. The rate of fluctuation for these parameters was higher during use of a VDT than use of a hard-copy. The time lag at five hours of VDT work was extended by 90% based on the value at the pre-work. The symptoms of general fatigue and fatigue of the eyes increased linearly during the VDT work for six hours. The results indicated a significant correlation between the objective parameters for the activity of the spontaneous blinks, i.e., duration and amplitude of EMG and EOG, and the time lag between EMG and EOG, and the subjective feeling was recognized in the time course of the task. These experimental results suggested that the parameters regarding the EMG and the EOG for the spontaneous blinks were effective indices for assessing visual fatigue during prolonged VDT work.     

Icosahedral quasicrystal in annealed ZnMgSc alloys

A new icosahedral quasicrystal has been found in Zn 85-x Mg x Sc 15 ( x = 3,4,5) alloys annealed at 922K for 5-100h. Electron diffraction and powder X-ray diffraction experiments indicate that this quasicrystal has a primitive icosahedral quasilattice (P type) and a six-dimensional lattice parameter a 6D =0.7115nm. The stoichiometric composition of the icosahedral quasicrystal was estimated to be close to Zn 80 Mg 5 Sc 15, since the icosahedral quasicrystal coexists in the x = 5 samples with small amounts of a MgZn 2 -type Laves phase and a Zn 17 Sc 3 -type cubic phase with lattice parameter a =1.3854nm. The latter is interpreted to be a 1/1-type approximant crystal of the icosahedral quasicrystal. The atomic cluster included in the Zn 17 Sc 3 -type cubic phase indicates a structural similarity between the Zn-Mg-Sc quasicrystal and the Cd-Yb (and Cd-Ca) icosahedral quasicrystals recently reported.     

Adolescent mental health in Japan and Russia: The role of body image,bullying victimisation and school environment

This study examined associations between self-reported mental health problems, body image, bullying victimisation and school safety in large adolescent samples in Japan and Russia, considering the effects of gender, culture and their interactions. In both Japan and Russia, girls reported a greater number of mental health problems, less bullying victimisation and much higher body dissatisfaction than boys did. Japanese adolescents rated themselves higher on total difficulties, reported less body dissatisfaction and bullying victimisation, and rated their school safety lower than that of Russian youths. Cross-cultural differences in total difficulties and body image were qualified by gender. Body dissatisfaction, bullying victimisation and school safety all independently contributed to adolescent mental health problems. The protective effect of school safety on total difficulties was larger for girls than for boys; the strength of the association between bullying victimisation and adolescent mental health problems differed across genders and cultures. The findings indicate a need for a cross-cultural approach and provide a strong basis for targeted interventions that seek to improve adolescent mental health.     

Interocular transfer of a rotational motion aftereffect as a function of eccentricity

In previous psychophysical investigations it has been reported that the angular extent over which the human visual field is served by binocular neurons in the visual cortex is limited to the central 40 degrees. However, these reports have been primarily based on data collected with static stimuli. Here we extend this investigation to include dynamic stimuli. Interocular transfer of the rotary motion aftereffect (rMAE) was measured for three stimulus diameters: 5, 30, and 62 deg. Interocular transfer, expressed as a percentage of monocular adapt/test rMAE duration was significantly reduced for stimulus diameter of 62 deg relative to 30 and 5 deg diameters. Nevertheless, interocular transfer durations still comprised a significant percentage of same-eye adapt/test durations (46.9%), comparable to previous reports of transfer MAE durations in near-central vision. The spatial extent of binocular interaction is likely stimulus specific and is still appreciable in the far periphery for complex-motion stimuli.     

Game Logic and its Applications II

This paper provides a Genzten style formulation of the game logic framework GLm (0 m ), and proves the cut-elimination theorem for GLm. As its application, we prove the term existence theorem for GL used in Part I.     

The effects of an improved residential nursery on the development of young Japanese children

The author, acting both as a researcher and a staff member, intervened at the residential nursery to facilitate the development of the children. The main goal of the intervention was to establish attachment relations between infants and their caretakers. The living environment of the institution simultaneously improved with the home-like atmosphere of small group care. Children's developmental status was examined before and after the intervention. The improved organization of the nursery was significantly correlated with the social (fear of stranger) and verbal (single word; first sentence) development of infants. This study showed how to facilitate normal development in children by improving residential nursery life. The results of two follow-up surveys in family-like residential nurseries, conducted independently in Germany and Japan, showed that early negative family experiences may be offset by favorable influences later in life, even at institutions. These findings suggests that quality of substitute care and family-like conditions, rather than residential care itself, may be the more important influences on children.     

Curiosity about a positive or negative event prolongs the duration of emotional experience

Some researchers claim that uncertainty prolongs the duration of emotional experiences because uncertainty toward an emotion-eliciting event prolongs attention to that event. However, some results contradict this claim. We assumed that curiosity rather than uncertainty prolongs the duration of emotional experience via attention, and that attention and emotional experience are prolonged only when uncertainty elicits curiosity. This assumption is based on the information gap theory, which proposes that curiosity increases with uncertainty, but that curiosity decreases at a certain level of uncertainty. We conducted a survey study to investigate the relationships among curiosity, uncertainty, attention and duration of positive and negative emotional experiences. The results showed that curiosity, but not uncertainty, prolonged the duration of emotional experiences and the process was completely mediated by attention both for positive and negative emotions. Moreover, uncertainty prolonged the duration of emotional experiences only when uncertainty elicited curiosity, which in turn prolonged attention to the emotion-eliciting event.