A mathematical method for the turbulent behavior of crowds using agent particles
Teruaki Ohnishi
in Journal of Physics: Conf Ser., Vol.738(1) (2016), 012091
Among the people moving as a group there appear social and psychological forces together with physical forces as friction and resistance. With the definition that the field of the crowd is the region of those forces continuously extending with varying strength, and with the pre-requisite that the spatial distributon of the crowd, i.e, the distribution of the field, varies according to the hydrodynamical rule, a methodology was proposed to describe the behavior of the crowd as the movement of a compressible turbulent fluid. As for the feasiblity study of this method, a numerical calculation was exemplified for the dynamical behavior and apatial distribution of crowd during movement when there appaer a conflict between groups with different characters, imaging for instance the medieval battle of Breitenfeld.

大西 輝明、島野 圭司、岡田 修身
社会技術研究論文集 Vol.13 (May 2016), pp.43-52


Morphological Similarity of Road Networks and Cracks

by Teruaki Ohnishi, Osami Okada, and Hirofumi Shirakata
in Physica A, Vol 392, Issue 18 (15 September 2013), pp.4127-4133.

An investigation was made regarding to what extent road network patterns are reproduced by a crack model from a viewpoint that they seem to resemble crack patterns in morphology. A desiccation model using double-layered cellular meshes was considered with the parameters representing the anisotropy of material and the coarseness of grains, together with the introduction of singularities in points and in lines. The model can generally reproduce the real crack patterns and the road network patterns of cities with characteristic morphology of appropriately choosing the values of parameters, indicating that the similar mechanism acts on the formation of road networks and crack of materials although the relevant scales of space time differ from each other. Factors which make the road networks more complex and irregular in morphology were also investigated.
Keywords: road network, crack pattern, morphological similarity, cellular mesh model, simulation.

Environmental Attitude of Young Nepalese and its Comparison with the Attitude of Environmentally Developed Costa Ricans
Teruaki Ohnishi, Shree Ram Khadka, Gustavo Hernandez Sanchez, Tanka Nath Dhamala
in International Journal of Sociology of Education, Vol. 2(1), 2013, pp.26-50.


Cognition surveys on environmental attitudes and values, together with the extent of scientific knowledge, were carried out in Costa Rica and Nepal in 2009 and 2012, respectively, for the university students of an average age of around 20, and Nepalese attitudes were compared to the attitudes of Costa Rican from the viewpoint of cultural background.  The surveys were made in classrooms by using printed questionnaire consisted of about 60 questions of the type selecting the answer from multiple choices.  Summed results were shown for both nations on the view of values and knowledge regarding environmental problems, attitudes to the environmental deterioration, ethical responsibility to the problems, probable outcome of environmental condition in future, and the type of environmental problems considered to be important for respective country.  From the comparison of attitudes between two nations, Nepalese were found to hold moderate attitudes to almost all environmental problems without expressing any clear opinions, whereas Costa Ricans have distinct and unified opinions common to all members indicating strong internalization of environmental thought.  

岡田 修身
Bilbia, No.60, January 2013, pp.33-37.


The Behavior of Radiolytically produced Hydrogen in a High-level Liquid Waste Tank of a Reprocessing Plant: Hydrogen Concentration under γ-irradiation of the Simulated Solution
by T.Kodama, M.Nakano, K.Fujita, S.Matsuoka, Y.Ito, C.Matsuura, H.Shiraishi, Y.Katsumura
Nuclear Technology, Volume 180(1), 2012, pp.103-110

Simulated high-level liquid waste was irradiated by 60Co gamma radiation, and changes in the gas-phase concentration of the products H2, O2 and NOxthat accumulated in the absence of sweeping air were measured. The H2 concentration reached a steady-state value of much less than 4% in line with the value predicted from the previously derived mathematical expression. The simulated dissolver solution was also irradiated, and another steady-state H2 concentrarion of much less than 4% was obtained in accordance with the corresponding predicted value. These experimental results lend strong support for applicability of a mathematical expression in predicting the H2 concentration in a tank in the case of a sweeping-air function loss.

Evolution of Groups with a Hierarchical Structure
Teruaki Ohnishi
in Physica A, volume 391, 2012, pp.5978-5986.

The universal occurrence of a hierarchical structure and its dynamic behavior in various types of group, living or abstract, are discussed. Here the word ‘‘group’’ refers not only to tangible aggregation but also to invisible aggregation of social psychological and of geopolitical meaning. The evolution of these groups is simulated using a model of agents distributed on the lattices of cellular grids. It is assumed that agents, fearing isolation, interact asymmetrically with each other with regard to exchange of ‘‘power’’. As an indicator of hierarchy, the Gini coefficient is introduced. Example calculations are made for the aggregation, fusion and fission of animal groups, and for the appearance of a powerful empire and the rise and fall of supremacy. It is shown that such abstract objects evolve with time in accordance with the universal rules of groups common to birds and fish.

Como un Voluntario Extranjero Influye en el Publico ?
by Teruaki Ohnishi, Shimako Funabashi
in Revista del Ciencias Sociales, numero 128-129, volumea II-III, 2010, pp.181-191.

The feature of volunteer's activity which influences on the consciousness and attitude of the public was studied using a model of mathematical sociology. The activity of the volunteer puts the public consciousness in a perturbed state. Its extent, together with the time-varying feature of the consciousness, change depending on both the strength of the volunteer's activity and on the difference of the view of values between the volunteer and the society as a subject. The effect of such volunteer's activity on the Costa Ricans and some implications from the simulation are generally discussed. (original article in Spanish)



Study on the Behavior of Radiolytically Produced Hydrogen in a High-level Liquid Waste Tank of a Reprocessing Plant: Hydrogen Consumption Reaction Catalyzed by Pd Ions in the Simulated Solusion
by T.Kodama, M.Nakano, K.Fujita, S.Matsuoka, Y.Ito, C.Matsuura, H.Shiraishi, Y.Katsumura
Nuclear Technology, Volume 172, 2010, pp.77-87

It is well known that not all of the hydrogen formed in high-level liquid waste comes out in the gas phase because hydrogen is consumed by some unclarified secondary reaction. Using a simulated waste solution, it was found that the H2 consumption reaction is not caused by radiation as was thought but is caused by a catalytic effect of Pd ions, which suggests that the same reaction proceeds in actual solution. Using the catalytic reaction rate constant measured in the simulated solution, the analysis showed that the H2 concentration in the gas phase does not reach its explosion limit of 4% even if the sweeping air stops for a long time.

Conceptual Design of 1,000 MWth Inherently Safe Fast Reactor (ISFR)
Yoshiro Asahi (英文PDF 240kB)
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles (FR09) (2009 Dec., Kyoto)

ISFR is a boiling heavy water reactor inherent ultimate safety (PIUS) type with a positive void coefficient. Fuel breeding may occur in the core. Unlike PIUS, however, the primary system does not contain boron. In accidents, ISFR shutdowns passively occur, because, due to the positive void coefficient, a negative reactivity will be induced by ingress of cold pool water into the circulating primary system (CPS). Since ISFR has not only the positive void coefficent, but also voids in the reactor already at the steady state, the PIUS concept must be modified so that safety and stability can be ensured. To this end, (1) a mixture of He and Ar is used as the gas so that the time constants of the positive void feedback process can be sufficiently large, (2) initially-closed two-way check valves to be used as passive switches are installed at the lower honeycombs and (3) a reactor control system is designed. As a result, ISFR can be stabilized enough to perform not only constant power operations, but also power level shift. Item (1) and (2) also help ensure safety of ISFR, because item (1) slows downthe positive feedback, while item (2) speeds up an actuation of the ISFR shutdown mechanism. In long term cooling after reactor shutdown, heat pipes effectively transfer decay heata to the atmosphere. Much work is still needed to prove feasibility of ISFR.

翻訳「未来の私たち」("Tomorrow's People" by Susan Greenfield)
(2008年2月、発行 NPO科学技術社会研究所、発売 産業図書)


Conceptual Design of Inherently Safety Fast Reactor with Reactor Control System
by Yoshiro Asahi (英文PDF 251kB)
in Proceedingd of ARWIF 2008, OECD/NEA/NSC (2008, Feb.., Fukui)

ISFR is a boiling heavy water fast reactor, which is of process inherent ultimate safety (PIUS) type. Unlike PIUS,however, the primary system of ISFR does not contain boron. ISFR may breed fuel in the core. The fuel contain minor actinides. It is shown that safety and control problems resulting from a positive void coefficient may be resolved by modifying the PIUS concept.

Assessing the Effect of Global Climate Change on the Future Jordanian Society (II) : Implication
Teruaki Ohnishi and Wa'il R. Tyfour
Dirasat, Volume 34, No.1, 2007, pp.20-35

An investigation was made on what strategic policy-making is required under the condition of global climatic change in sectors of energy, water and agriculture in Jordan, using a mathematical model previously developed to assess the future Jordanian society. According to this model, the increase in consumption resulting from the growth of both population and personal consumption was found to greatly exceed the increase of production in all sector in Jordan throughout this century, especially in the case of climatic change. The introduction of distributed energy sources for insuring energy security, further efficient use of rain water and the introduction of new technologies such as desalinization, for instance, for water security, and the appropriate adaptation for the agriculture were pointed out as for the tactical policies in each sectors. Moreover, the importance of public awareness of the crises of energy, water and food is pointed out. Also, the necessity of building capacities for bringing up leaders to practice the adaptation, and the urgency of making long-term strategic policies in all sectors is emphasized.

Assessing the Effect of Global Climate Change on the Future Jordanian Society (I) : A Mathematical Model
Teruaki Ohnishi and Wa'il R. Tyfour
Dirasat, Volume 33, No.2, 2006, pp.138-158

A calculation model was developed to forecast and assess the effect of global climate change on the future of energy use, water sufficiency and agricultural production in Jordan. For the purpose of this study, the world is divided into three regions: Jordan, Arab league countries and the rest of the world. Interaction between these regions is assumed to take place in the form of agricultural product exchange. Considering the sectors of energy, water, and agriculture in Jordan from the viewpoint of systems' concepts, the future behavior of their quantities are formulated under conditions of climate change. These quantities are: energy consumption, water supply and demand, and the production and consumption of agricultural products. An example calculation is made and the behavioral features of those quantities from the year 2000 to 2100 are derived under the constraint that the total amount of the world wide production of a certain agricultural product is equal to the total amount of its consumption. The results shows that the amount of energy, water and agricultural products required for Jordan will become remarkably high, especially in the second half of this century. This strongly emphasizes the need for appropriate policies to tackle the deficits. The developed model appears suitable for assessing the adequacy of the policies that should be implemented in future Jordan regarding the management of the sectors of energy, water and agriculture.