November 2025 Vol. 23 No. 11

View from the Top

• Ichiro Uehara, President, NTT Infrastructure Network Corporation

  

  Abstract
  NTT Infrastructure Network Corporation (NTT InfraNet) is tackling a variety of social challenges, such as aging facilities, labor shortages, environmental issues, and disaster prevention, by applying the technical capabilities it has cultivated through its business—namely, providing information and communications infrastructure—and co-creation with its partners. The efforts of NTT InfraNet to contribute to the optimization and sustainability of Japan’s social infrastructure as a whole is drawing considerable attention. We spoke with Ichiro Uehara, President of NTT InfraNet, which builds and operates social infrastructure for a new era, about the development of NTT InfraNet’s business and his role as leader.

Front-line Researchers

• Tessei Kobayashi, Senior Distinguished Researcher, NTT Communication Science Laboratories

  

  Abstract
  The Ministry of Education, Culture, Sports, Science and Technology (MEXT) reported that in the National Academic Achievement Test conducted in April 2025 for third-grade junior high school students, the correct rate for the essay-style questions in Japanese language, which required students to express their own thoughts in writing, was just 25.6% on average. Some questions had non-response rates of nearly 30%. To understand the essence of a question and to express one’s thoughts requires language skills, which are acquired through linguistic inputs from parents, teachers, and others during infancy and early childhood. Tessei Kobayashi, a senior distinguished researcher at NTT Communication Science Laboratories, has conducted research on child language development. During his research, he proposed and supervised individually optimized picture books, which contribute to educational support for infants and young children. We spoke with him about his thoughts on applying his research findings on “the development of the human mind” as a support tool in the field of child education.

Rising Researchers

• Takafumi Tanaka, Distinguished Researcher, NTT Network Innovation Laboratories

  

  Abstract
  The Internet services we take for granted every day are supported by optical communication technology, which enables long-distance, high-capacity communications, and many pieces of equipment, including optical fiber cables and optical transceivers. However, many challenges remain, such as the increasing complexity of optical network design as optical communication technology evolves and the need to address the cost savings associated with the ever-increasing amount of communication equipment. Even under these circumstances, using design technology for configuring optimal communication paths will make it possible to support more communication traffic economically even with existing communication equipment and facilities. We spoke with Takafumi Tanaka, a distinguished researcher at NTT Network Innovation Laboratories and a leader in optimal communication path design technology.

Feature Articles: AI Constellation—Toward a World in Which People and AI Work Together

• AI Constellation—Collaboration among Diverse AI Models

  

  Abstract
  NTT has been promoting AI Constellation since FY2023 as a large-scale artificial intelligence (AI) collaboration technology that enables different AI systems to hold discussions and correct each other to generate solutions from diverse perspectives for problems with causes that are difficult for humans to infer. This article provides the background and details leading up to this concept, such as AI technology trends, capabilities that need to be acquired, and related use cases, and the relationship between AI Constellation and NTT’s IOWN (Innovative Optical and Wireless Network) vision for the future.

• Research and Development toward AI Constellation

  

  Abstract
  Discussions held within a multi-agent system, such as AI Constellation, are expected to solve problems on the basis of diverse viewpoints by using multiple large language models (LLMs). However, simply combining language models results in generating similar and abstract responses, and the lack of deep discussions has become an issue. This article introduces LLM-agent response-diversifying technology for automatically selecting new viewpoints while maintaining discussion flow.

• Field Trial and Future Outlook of AI Constellation

  

  Abstract
  This article introduces a field trial of AI Constellation—a large-scale artificial intelligence (AI) collaboration technology—titled “Conference Singularity,” held in Omuta City, Fukuoka Prefecture. Through AI-to-AI discussions using AI Constellation, we explored how ideas and opinions from diverse perspectives can be generated around complex issues, such as regional challenges, which lack a single solution due to differing stakeholder viewpoints. The trial confirmed that this approach can help deepen human discussion and lead to concrete new insights.

• Advanced Research on AI Algorithms for Supporting AI Constellation

  

  Abstract
  The following four examples of NTT’s research on cutting-edge artificial intelligence (AI) algorithms to be used as basic techniques for AI Constellation—a large-scale AI collaboration technology—are introduced in this article: (i) “learning transfer,” which enables the reuse of learning results; (ii) “transfer learning” that can adapt to environmental changes in imbalanced data with low labeling costs; (iii) “test-time-adaptation” for numerical-prediction models; and (iv) “sparse modeling” for analyzing a wide variety of large-scale, high-dimensional data.

Feature Articles: Security R&D for a Better Future

• Changes in the Environment Surrounding Security R&D and NTT Social Informatics Laboratories’ Challenges

  

  Abstract
  Based on more than 40 years of the world’s most advanced cryptography research and 20 years of pioneering cybersecurity research, NTT Social Informatics Laboratories is engaged in security research and development (R&D), contributing to the development of society by materializing new activities and businesses that were previously abandoned due to their inability to tolerate risks while contributing to the defense of society. This article introduces our approach to security R&D and the latest priority research themes.

• Research Initiative for Safe AI Use from a Security Perspective

  

  Abstract
  Large language models (LLMs) are significantly improving business process efficiency by automating tasks such as meeting minute creation and the translation and summarization of reports. However, systems that leverage LLMs face threats stemming from artificial-intelligence-specific vulnerabilities that cannot be fully addressed by conventional information-technology security technologies. This article introduces representative threats unique to LLMs, recent trends in defense methods against them, and the research initiatives by NTT Social Informatics Laboratories.

• Collaboration between People and AI to Evolve Security Activities into a New Form for People

  

  Abstract
  Cyber-attacks targeting systems are intensifying yearly, and the shortage of security personnel is becoming serious. Therefore, a fundamental review of security operations based on automation using artificial intelligence (AI) is required. In today’s information society, it is difficult to maintain people’s autonomous decision-making due to misinformation and disinformation, and the object of security is expanding from systems to human cognition. In this article, we introduce innovative cybersecurity operations using generative AI and cognitive security that supports autonomous human decision-making.

• Toward a Digital-data-enhanced Economy—Information Sharing Driven Using Digital Wallets for Individuals and Enterprises

  

  Abstract
  With a view to a digital-data-enhanced economy based on information sharing driven using digital wallets, NTT is researching and developing techniques for ensuring the trust in digital information, achieving encryption/decryption control, and enabling the secure and trusted use of digital data. On the basis of the three pillars of information authenticity, controllability, and security, we aim to develop platform technologies that will enable the use of trustworthy information that protects privacy through a digital identity wallet, decentralized trust, secure computation, etc.

• Cryptography Research in Anticipation of the Advent of the Quantum-computer Era

  

  Abstract
  NTT Social Informatics Laboratories is engaged in the research and development of the world’s top-level cryptography and security technologies that will contribute to social change and solving social problems in the quantum-computer era. In this article, we introduce the research on and standardization of post-quantum cryptography, research and development of crypto-agility technologies that contribute to the transition from modern cryptography to post-quantum cryptography, and research on new security technology that integrates cryptography and quantum information processing.

Regular Articles

• Space and Wavelength Multiplexed Programmable Photonic Processors

  

  Abstract
  Photonic computing based on programmable photonic processors is raising interest as it promises massively parallelized computation with low energy consumption for tensor processing in machine learning by harnessing inherent parallelism of light. In this article, we describe our recent progress in scaling up photonic computing platforms, including our development of a large-scale photonic matrix-vector processor and on-chip photonic linear processor. We experimentally demonstrate the applications of our processors to a machine-learning accelerator and pre-processor for optical communications.

Global Standardization Activities

• Technical Trends in ISO/IEC Joint Technical Committee 1

  

  Abstract
  The International Organization for Standardization (ISO)/International Electrotechnical Commission (IEC) Joint Technical Committee (JTC) 1 is an organization established by ISO and IEC and is responsible for international standardization in the field of information technology. This article introduces the activities being addressed by subgroups directly under JTC 1, which were identified in resolutions from recent ISO/IEC JTC 1 Plenaries.

Practical Field Information about Telecommunication Technologies

• Countermeasures to Lightning Damage for Outdoor-installed Optical Access Equipment (RSBM-F)

  

  Abstract
  This article presents an example of a failure of an RSBM-F (remote subscriber module feeder point), outdoor-installed optical access equipment, due to lightning surges and countermeasures taken against such failure.