# Fileset

[[Vol. 44]Ionic Devices Learn How to Make Decisions_WPI-MANA.pdf](https://mdr.nims.go.jp/filesets/57926ab3-de60-4450-b34e-d5432a952160/download)

## Creator

International Center for Materials Nanoarchitectonics (WPI-MANA)

## Rights

In Copyright[In Copyright](http://rightsstatements.org/vocab/InC/1.0/)

## Other metadata

[[Research Highlights Vol.44] Ionic Devices Learn How to Make Decisions](https://mdr.nims.go.jp/datasets/caf4a528-ba7b-479b-a853-ac8dbe41f3c3)

## Fulltext

2022/04/04 10:03 Ionic Devices Learn How to Make Decisions| MANAhttps://www.nims.go.jp/mana/research/highlights/vol44.html 1/3Previous  Index  NextResearch Highlights[Vol. 44]Ionic Devices Learn How to Make Decisions19 Dec, 2018Decision-making processes require the examination of complex data in order to effectively adapt todynamic changes in the environment and make decisions about the most appropriate way tobehave. Emulating these processes with computers requires enormous resources, so new avenuesneed to be explored.Now, writing in Science Advances, Takashi Tsuchiya, Tohru Tsuruoka, Song-Ju Kim (currently atKeio Univ.), Kazuya Terabe and Masakazu Aono at the World Premier International Center forMaterials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS),Tsukuba, Japan propose to use ionic devices to perform decision-making operations. They applytheir devices, named ionic decision-makers, to the solution of multiarmed bandit problems (MBPs);mathematical problems in which a gambler given a choice of slot machines must select theappropriate machines to play so as to maximize the total reward in a series of trials. MBPs havebeen applied to various practical technologies related to artificial intelligence. The scenarioinvestigated by the authors is that of a user of busy communication channels who needs to select achannel to transmit information with maximum efficiency.A two-electrode electrochemical cell, with Nafion proton conducting polymer electrolyte and Ptelectrodes, is used to solve MBPs with two channels (A and B), with transmission probabilitiesPA and PB, of which the user has no a priori knowledge. The setup comprises the cell, a devicecontrolling the flow of electric current through it, and a random number generator that determineshttps://www.nims.go.jp/mana/research/highlights/vol43.htmlhttps://www.nims.go.jp/mana/research/highlights/index.htmlhttps://www.nims.go.jp/mana/research/highlights/vol45.html2022/04/04 10:03 Ionic Devices Learn How to Make Decisions| MANAhttps://www.nims.go.jp/mana/research/highlights/vol44.html 2/3the transmission of data packets. The electrical potential of each of the two electrodes, A and B, isused to evaluate which channel is the best to select, and it increases or decreases on the basis ofwhether or not the channel is open for transmission.Ions in the electrolyte are initially randomly distributed, but there is still a small voltage across thedevice. This voltage is measured; if it is positive (negative), a random number is generated toemulate the selection of channel A (B), that is, to determine whether a packet is transmitted ornot. In accordance with the result, a pulse current is then applied in the corresponding polarity,varying the concentration of ions and/or molecules in the vicinity of the electrodes. The rate ofcorrect selection increases with the number of selections, because the variation in theconcentration near the electrodes makes it a more or less likely choice in subsequent selections. Toverify the adaptability of the system to environmental changes, PA and PB was inverted after someselections; the rate of correct selections initially dropped, but the decision maker quickly adapted.A more complex problem is that of two network users trying to select an available channel. If theyselect the same channel the probability of it being open is split between them, so that the numberof transmitted packets decreases substantially for both. This is an important practical problem forcommunication network systems with limited channels and many users. The authors present anextended decision maker, with two electrochemical cells and three channels, which is particularlyeffective at solving such problem and can maximize the number of packets for all users.The authors comment, “The ionic decision-maker creates a new research field of ‘materialsdecision-making’ in which the intrinsic properties of materials are used to make decisions, not onlyfor large-scale computations of human behavior but also for developing autonomous intelligentchips for mobile applications.”Reference"Ionic decision-maker created as novel, solid-state devices"Takashi Tsuchiya, Tohru Tsuruoka, Song-Ju Kim, Kazuya Terabe and Masakazu AonoJournal : Science Advances 4, eaau2057 (2018).DOI : 10.1126/sciadv.aau2057AffiliationsInternational Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for MaterialsScience (NIMS), Namiki 1-1, Tsukuba, Ibaraki 305-0044, JapanContact informationInternational Center for Materials Nanoarchitectonics(WPI-MANA)National Institute for Materials Science1-1 Namiki, Tsukuba, Ibaraki 305-0044 Japanhttps://samurai.nims.go.jp/profiles/tsuchiya_takashi?locale=enhttps://samurai.nims.go.jp/profiles/tsuruoka_tohru?locale=enhttps://samurai.nims.go.jp/profiles/terabe_kazuya?locale=enhttps://samurai.nims.go.jp/profiles/aono_masakazu?locale=enhttps://advances.sciencemag.org/content/4/9/eaau20572022/04/04 10:03 Ionic Devices Learn How to Make Decisions| MANAhttps://www.nims.go.jp/mana/research/highlights/vol44.html 3/3Phone: +81-29-860-4710E-mail: mana-pr[AT]ml.nims.go.jp