Frontiers of Information Technology & Electronic Engineering最新文献

While large language models (LLMs) have made significant strides in natural language processing (NLP), they continue to face challenges in adequately addressing the intricacies of the Chinese language in certain scenarios. We propose a framework called Six-Writings multimodal processing (SWMP) to enable direct integration of Chinese NLP (CNLP) with morphological and semantic elements. The first part of SWMP, known as Six-Writings pictophonetic coding (SWPC), is introduced with a suitable level of granularity for radicals and components, enabling effective representation of Chinese characters and words. We conduct several experimental scenarios, including the following: (1) We establish an experimental database consisting of images and SWPC for Chinese characters, enabling dual-mode processing and matrix generation for CNLP. (2) We characterize various generative modes of Chinese words, such as thousands of Chinese idioms, used as question-and-answer (Q&A) prompt functions, facilitating analogies by SWPC. The experiments achieve 100% accuracy in answering all questions in the Chinese morphological data set (CA8-Mor-10177). (3) A fine-tuning mechanism is proposed to refine word embedding results using SWPC, resulting in an average relative error of ≤25% for 39.37% of the questions in the Chinese wOrd Similarity data set (COS960). The results demonstrate that SWMP/SWPC methods effectively capture the distinctive features of Chinese and offer a promising mechanism to enhance CNLP with better efficiency.

人工智能生成内容(AIGC)是近年来人工智能(AI)领域一个研究热点,它有望取代人类以较低成本高效率执行内容生成工作,如音乐、绘画、多模态内容生成、新闻文章、总结报告、股评摘要,以至元宇宙中的内容生成和数字人。AIGC为未来AI发展和实现提供了一条新的技术路径。

在此背景下,《信息与电子工程前沿(英文)》期刊组织了一期关于AIGC最新进展的特刊。本期特刊关注AIGC理论、算法、应用及相关领域。通过吸引高质量论文,我们希望帮助学术界和工业界研究人员更深入了解AIGC背后的基本理论及其潜在应用,激励更多研究人员加入并推进AIGC领域的研究。因此,我们就以下主题(但不限于)征集论文:(1)AI生成音乐;(2)AI生成绘画;(3)AI对话模型;(4)AI新闻摘要;(5)AI与元宇宙;(6)AI与数字人;(7)AI图像编辑;(8)AI生成短视频;(9)AI生成多媒体内容;(10)ChatGPT相关工作。经严格评审,选出12篇论文,包括1篇评论、1篇观点、3篇综述、6篇研究和1篇通讯。我们将其划分为3个主要部分:ChatGPT、扩散模型、提示学习和多模态。

总体而言,本期特刊涵盖了与AIGC开发和应用相关的广泛研究主题,包括人工智能图像/文本生成、三维内容创建、以用户为中心的图形设计、特定风格的音乐生成,以及与因果表征学习、高阶扩散模型相关的工作。此外,还详细调研了概率扩散模型、提示学习和ChatGPT。

最后,感谢所有作者对本期特刊的支持,特别感谢所有评审人对专刊投稿富有见地的意见和有益建议。

Recently, various algorithms have been developed for generating appealing music. However, the style control in the generation process has been somewhat overlooked. Music style refers to the representative and unique appearance presented by a musical work, and it is one of the most salient qualities of music. In this paper, we propose an innovative music generation algorithm capable of creating a complete musical composition from scratch based on a specified target style. A style-conditioned linear Transformer and a style-conditioned patch discriminator are introduced in the model. The style-conditioned linear Transformer models musical instrument digital interface (MIDI) event sequences and emphasizes the role of style information. Simultaneously, the style-conditioned patch discriminator applies an adversarial learning mechanism with two innovative loss functions to enhance the modeling of music sequences. Moreover, we establish a discriminative metric for the first time, enabling the evaluation of the generated music’s consistency concerning music styles. Both objective and subjective evaluations of our experimental results indicate that our method’s performance with regard to music production is better than the performances encountered in the case of music production with the use of state-of-the-art methods in available public datasets.

Physical layer key generation (PKG) technology leverages reciprocal channel randomness to generate shared secret keys. However, multipath fading at the receiver may degrade the correlation between legitimate uplink and downlink channels, resulting in a low key generation rate (KGR). In this paper, we propose a PKG scheme based on the pattern-reconfigurable antenna (PRA) to boost the secret key capacity. First, we propose a reconfigurable intelligent surface (RIS) based PRA architecture with the capability of flexible and reconfigurable antenna patterns. Then, we present the PRA-based PKG protocol to improve the KGR via mitigation of the effects of multipath fading. Specifically, a novel algorithm for estimation of the multipath channel parameters is proposed based on atomic norm minimization. Thereafter, a novel optimization method for the matching reception of multipath signals is formulated based on the improved binary particle swarm optimization (BPSO) algorithm. Finally, simulation results show that the proposed scheme can resist multipath fading and achieve a high KGR compared to existing schemes. Moreover, our findings indicate that the increased degree of freedom of the antenna patterns can significantly increase the secret key capacity.

智能超表面(RIS)是一种具有可重构电磁特性的二维人工材料. 通过改变嵌入RIS元件中的可调谐器件的控制信号, 可独立地调整每个元件表面电磁波的相位、振幅、偏振和频率响应, 因此能够以可编程的方式重塑空间电磁波的波前. RIS提供了强大的能力来控制无线传播环境, 提高无线通信网络的性能, 同时具有低复杂性、 结构简单、 低成本的优点, 在无线覆盖扩展、 无线覆盖增强以及无线系统容量的提高方面具有很好的优势. 目前, RIS辅助无线通信技术的发展聚焦以下几个关键点:

1. 1. RIS硬件的低功耗、 低成本设计

   在RIS开发过程中, 功耗和系统成本是其未来大规模部署的两个关键因素. 控制和驱动电路及其可调谐组件的功耗通常在系统功耗中比例较高. 微波材料和射频(RF)部件的有效成本控制也很重要. 如何实现功耗、 成本和性能之间的良好平衡在很大程度上取决于先进的设计技术和创新的解决方案.

2. 2. 新硬件架构和模型下的RIS波束形成设计

   随着RIS技术的进步, RIS硬件在网络中的配置愈发多样化. RIS与放大转发(AF)中继的结合有望平衡硬件成本和通信速率之间的关系. 通过引进新型RIS, 进一步实现传输波和反射波的联合调控, 并实现全向空间的完整覆盖. 此外, 还可引入RIS的宽带信道模型和现实功耗模型, 以支持RIS波束成形和能效性能的联合优化.

3. 3. RIS的新应用和标准化考虑

   RIS技术的引入为物理层通信安全带来新的维度. 基于RIS的物理层密钥生成协议可以通过反射模式的动态优化来提高密钥容量. 优化基站发射功率和RIS无源波束成形有助于减少干扰. 此外, RIS标准化讨论及其在工程中的应用研究也是非常迫切的, 从标准化的角度, 将RIS的性能与3GPP release-18(R18)中的网络控制中继器(NCR)进行比较很有意义.

目前, RIS在无线通信中的未来应用仍面临多重机遇与挑战. 为此, 中国工程院院刊《信息与电子工程前沿(英文)》组织了本期专题. 经严格评审, 选出12篇论文, 包括2篇综述和10篇研究, 涵盖了物理实现、 算法设计和标准化等热点话题.

Complex beams play important roles in wireless communications, radar, and satellites, and have attracted great interest in recent years. In light of this background, we present a fast and efficient approach to realize complex beams by using semidefinite relaxation (SDR) optimization and amplitude-phase digital coding metasurfaces. As the application examples of this approach, complex beam patterns with cosecant, flat-top, and double shapes are designed and verified using full-wave simulations and experimental measurements. The results show excellent main lobes and low-level side lobes and demonstrate the effectiveness of the approach. Compared with previous works, this approach can solve the complex beam-forming problem more rapidly and effectively. Therefore, the approach will be of great significance in the design of beam-forming systems in wireless applications.

Scholars are expected to continue enhancing the depth and breadth of theoretical research on reconfigurable intelligent surface (RIS) to provide a higher theoretical limit for RIS engineering applications. Notably, significant advancements have been achieved through both academic research breakthroughs and the promotion of engineering applications and industrialization. We provide an overview of RIS engineering applications, focusing primarily on their typical features, classifications, and deployment scenarios. Furthermore, we systematically and comprehensively analyze the challenges faced by RIS and propose potential solutions including addressing the beamforming issues through cascade channel decoupling, tackling the effects and resolutions of regulatory constraints on RIS, exploring the network-controlled mode for RIS system architecture, examining integrated channel regulation and information modulation, and investigating the use of the true time delay (TTD) mechanism for RIS. In addition, two key technical points, RIS-assisted non-orthogonal multiple access (NOMA) and RIS-based transmitter, are reviewed from the perspective of completeness. Finally, we discuss future trends and challenges in this field.

Reconfigurable intelligent surfaces (RISs) have the capability to change the wireless environment smartly Considering the attenuation of subchannels and crowding users involved in the wideband system, we introduce RISs into the multi-user multi-input single-output (MU-MISO) system with orthogonal frequency division multiplexing (OFDM) for performance enhancement. Maximizing the minimum rate of dense users in an MU-MISO-OFDM system assisted by RIS with an approximate practical model is formulated as the joint optimization problem involving subcarrier allocation, transmit precoding (TPC) matrices at the base station, and RIS passive beamforming. A coalition-game subcarrier allocation (CSA) algorithm is proposed to solve space–frequency resource allocation on subcarriers, which reforms the interference topology among dense users. Fractional programming and convex optimization method are used to optimize the TPC matrices and the RIS passive beamforming, which improves the spectral efficiency synthetically across all subchannels in the wideband system. Simulation results indicate that the CSA algorithm provides a significant gain for dense users. Besides, the proposed joint optimization method shows the considerable advantage of the RISs in the MU-MISO-OFDM system.

The wavefront control of spin or orbital angular momentum (OAM) is widely applied in the optical and radio fields. However, most passive metasurfaces provide limited manipulations, such as the spin-locked wavefront, a static OAM combination, or an uncontrollable OAM energy distribution. We propose a reflection-type multi-feed metasurface to independently generate multi-mode OAM beams with dynamically switchable OAM combinations and spin states, while simultaneously, the energy distribution of carrying OAM modes is controllable. Specifically, four elements are proposed to overcome the spin-locked phase limitation by combining propagation and geometric phases. The robustness of these elements is analyzed. By involving the amplitude term and multi-feed technology in the design process, the proposed metasurface can generate OAM beams with a controllable energy distribution over modes and switchable mode combinations. OAM-based radio communication with four independent channels is experimentally demonstrated at 14 GHz by employing a pair of the proposed metasurfaces. The powers of different channels are adjustable by the provided amplitude term, and the maximum crosstalk is −9 dB, proving the effectiveness and practicability of the proposed method.

The use of a reconfigurable intelligent surface (RIS) in the enhancement of the rate performance is considered to involve the limitation of the RIS being a passive reflector. To address this issue, we propose a RIS-aided amplify-and-forward (AF) relay network in this paper. By jointly optimizing the beamforming matrix at AF relay and the phase-shift matrices at RIS, two schemes are put forward to address a maximizing signal-to-noise ratio (SNR) problem. First, aiming at achieving a high rate, a high-performance alternating optimization (AO) method based on Charnes–Cooper transformation and semidefinite programming (CCT-SDP) is proposed, where the optimization problem is decomposed into three subproblems solved using CCT-SDP, and rank-one solutions can be recovered using Gaussian randomization. However, the optimization variables in the CCT-SDP method are matrices, leading to extremely high complexity. To reduce the complexity, a low-complexity AO scheme based on Dinkelbachs transformation and successive convex approximation (DT-SCA) is proposed, where the variables are represented in vector form, and the three decoupling subproblems are solved using DT-SCA. Simulation results verify that compared to three benchmarks (i.e., a RIS-assisted AF relay network with random phase, an AF relay network without RIS, and a RIS-aided network without AF relay), the proposed CCT-SDP and DT-SCA schemes can harvest better rate performance. Furthermore, it is revealed that the rate of the low-complexity DT-SCA method is close to that of the CCT-SDP method.