May 2022 Vol. 20 No. 5

Front-line Researchers

• Hiroshi Sawada, Senior Distinguished Researcher, NTT Communication Science Laboratories

  

  Abstract
  From his extensive research in blind source separation, Senior Distinguished Researcher Hiroshi Sawada has received worldwide acclaim for his work with a domestic research partner on independent low-rank matrix analysis, namely, the development and integration of independent component analysis and non-negative matrix factorization. He has also ventured into the field of neural networks. We asked him about his research achievements and his attitude toward enhancing his research activities.

Rising Researchers

• Sousuke Imamura, Distinguished Researcher, NTT Space Environment and Energy Laboratories

  

  Abstract
  According to the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report, 57.7% of carbon dioxide (CO₂) emissions into the atmosphere are absorbed by forests, and 34.6% is absorbed by the ocean. In this article, we interviewed Distinguished Researcher Dr. Sousuke Imamura about “CO₂ reduction technology in the ocean based on application of the genome editing technology.”

Feature Articles: Development of IOWN with Global Partners

• Progress in the Development of IOWN Technology

  

  Abstract
  Technical improvements in full-stack layers are essential to develop a future infrastructure with higher capacity, lower latency, and lower power consumption toward a cyber-physical society. NTT announced its roadmap for this technology, the Innovative Optical and Wireless Network (IOWN), in April 2020 and has accelerated to implement the roadmap with global partners of the IOWN Global Forum (IOWN GF). IOWN GF developed and published a series of deliverables on Open All-Photonic Network (Open APN), IOWN for Mobile Network, Fiber Sensing for Open APN, Data-Centric Infrastructure, IOWN Data Hub, and a Reference Implementation Model. This article provides an overview of these deliverables and describes the growth of IOWN GF and its activities.

• Study on Open All-Photonic Network in IOWN Global Forum

  

  Abstract
  The IOWN Global Forum is developing the Open All-Photonic Network (Open APN) to provide direct optical paths between any location on demand to implement use cases of the Innovative Optical and Wireless Network (IOWN). This article describes the Open APN design goals and technical challenges as well as its functional architecture, with reference to the technical document “Open All-Photonic Network Functional Architecture” published in early 2022.

• Data-centric-infrastructure Functional Architecture

  

  Abstract
  Society is changing at a rapid pace due to technical innovations in Internet technologies and cloud computing. In the near future, ever-more refined artificial-intelligence applications are expected, working on ever-larger data sets. Implementing such applications requires increasing the computational capacity available to the providers of such newly emerging services. However, energy consumption of such services must be reduced to achieve ESG (environmental, social, and governance) and the sustainable development goals. To fulfill both of these objectives at the same time, a drastic rethink of computing infrastructure is required. With this in mind, the IOWN Global Forum is creating the data-centric-infrastructure (DCI) functional architecture. This article gives an overview of the first DCI functional architecture reference document about this next-generation computing foundation.

• Study of Storage Services at IOWN Global Forum

  

  Abstract
  The IOWN Data Hub is a new data service that integrates database, storage, and other functions required in the Innovative Optical and Wireless Network (IOWN) era. The IOWN Data Hub is intended to be commonly used by other applications by leveraging the advanced IOWN infrastructure while maintaining compatibility with existing applications. This article introduces the status and the released document of the IOWN Data Hub discussed in the IOWN Global Forum.

Regular Articles

• The Challenge to Develop an Artificial Photosynthesis Device that Fixes CO₂ Using the Sun

  

  Abstract
  Interest in reducing greenhouse gases, especially carbon dioxide (CO₂), as a measure against climate change is increasing not only in countries but also in companies around the world. The NTT Group has formulated a new vision for zero environmental impact and declared its intention to achieve carbon neutrality by 2040. We expect artificial photosynthesis that converts CO₂ and water (H₂O) into hydrocarbons and molecular oxygen (O₂) using solar energy to be a technology that contributes to CO₂ reduction. To introduce this technology to the market, it is necessary to improve its efficiency and durability. We propose a gas-phase CO₂ reduction reaction system to improve solar-to-hydrocarbon conversion efficiency η_STC and conducting basic research on electrodes that make up this system. We studied a nickel oxide/indium gallium nitride (NiO/InGaN) photoanode to achieve both high efficiency and long lifetime. We also studied a copper (Cu)-fiber cathode to improve efficiency. In our system using these electrodes, formic acid (HCOOH) was produced in 140 hours of continuous light irradiation, resulting in an η_STC of 0.16%.

Global Standardization Activities

• Latest Research Results and ITU-T Standardization Activities on Soft Errors Caused by Cosmic Rays

  

  Abstract
  Due to advances in digital transformation, it is important to take measures against soft errors caused by cosmic rays to maintain a safe and secure network. This article explains the latest research results on soft errors from NTT laboratories, commercialization of soft-error test technology, and standardization activities in the International Telecommunication Union - Telecommunication Standardization Sector (ITU-T).

External Awards/Papers Published in Technical Journals and Conference Proceedings

• External Awards/Papers Published in Technical Journals and Conference Proceedings