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Multi-access Edge Cloud (MEC) networks are powerful for providing emerging computation-intensive and latency-sensitive applications with low latency leveraging ubiquitous edge devices. These networks enable complex applications to be split into multiple components/subtasks and deployed among multiple edge servers with limited computation and communication resources. However, multiple subtasks within an application are dependent on each other. They cannot be executed in parallel, resulting in non-trivial resource waste when allocating resources to every subtask throughout the lifetime of the application. This article investigates the multi-component task offloading problem in MEC networks that addresses the dependencies among components and three-dimensional (3D) resource allocation, i.e., computation, communication, and time slots. The problem is NP-hard and challenging to solve due to the complex task dependencies, including triangular dependencies among multiple subtasks and the routing of edges between dependent subtasks. To address the challenge, we first propose a non-destructive task reconfiguration algorithm that transforms a task call graph into multiple sequential layers, breaking out the triangular dependency. Then, we develop a dePendency-awaRe task offloAding algorithm wIth taSk rEconfiguration (PRAISE) algorithm to maximize the total offloading benefit. PRAISE decouples the original problem into task offloading and 3D convex resource optimization. Simulation results show that PRAISE outperforms baselines with higher system benefits and lower resource costs.

Free space optical communication (FSO) has been becoming one of the main directions of future communication network due to its advantages of high transmission rate, small divergence angle, and strong confidentiality. The acquisition, tracking, pointing (ATP) sub-system is an important guarantee for stable communication of FSO system. In the AI-enabled ATP system, data augmentation algorithms are effective to reduce the size of the dataset for spot prediction, and thus to lower the system structural complexity. In this letter, we propose a novel data augmentation algorithm that introduces wavelet transform into the fusing-and-filling generative adversarial network (F2GAN). The wavelet transform is utilized to convert the image information from time domain to frequency domain. The diversity of the generated images obtained from the GAN model is thus enhanced with the richer details. The experimental results show that, compared to the F2GAN algorithm, the proposed algorithm can improve peak signal to noise ratio by 14.5%, structure similarity index measure by 11.8%, and learned perceptual image patch similarity by 21%, respectively.

CBP/p300 is a master transcriptional coactivator that regulates gene activation by interacting with multiple transcriptional activators. Dysregulation of protein–protein interactions (PPIs) between the CBP/p300 KIX domain and its activators is implicated in a number of cancers, including breast, leukemia, and colorectal cancer. However, KIX is typically considered “undruggable” because of its shallow binding surfaces lacking both significant topology and promiscuous binding profiles. We previously reported a dual-targeting peptide (MybLL-tide) that inhibits the KIX-Myb interaction with excellent specificity and potency. Here, we demonstrate a branched, second-generation analogue, CREBLL-tide, that inhibits the KIX-CREB PPI with higher potency and selectivity. Additionally, the best of these CREBLL-tide analogues shows excellent and selective antiproliferation activity in breast cancer cells. These results indicate that CREBLL-tide is an effective tool for assessing the role of KIX-activator interactions in breast cancer and expanding the dual-targeting strategy for inhibiting KIX and other coactivators that contain multiple binding surfaces.

Cooperative communication has been widely studied as an effective technique for free-space optical (FSO) systems to combat the effects of atmospheric conditions and beam misalignment. Related works on cooperative FSO communication mostly used a fixed splitter to uniformly distribute optical power for broadcast transmission, which tends to cause the insufficient utilization of optical power when the relay links have different channel statuses. In this paper, we focus on the optical power utilization of cooperative FSO communication, which remains less touched in previous works, while it is a decisive factor in system performance. We propose an elastic optical splitter structure to improve the efficiency of optical power by dynamically adjusting its optical output to the changing atmospheric channels. The elastic optical splitter brings a new chance for the relay selection and power allocation, which will become a different issue from that in traditional cooperative FSO systems. Thus, we further propose an adaptive relay selection and power allocation scheme using a deep reinforcement learning algorithm. Results demonstrate that the proposed elastic optical splitter is superior to the fixed optical splitter for cooperative FSO communication in bit error rate (BER) by a performance improvement of 1 to 2 orders of magnitude. Along with the proposed adaptive relay selection and power allocation scheme, the performance is further improved by more than 25% under different channel conditions.

Hybrid free space optical (FSO)/radio frequency (RF) system has emerged as a high-data-rate solution for the last mile access network. In this paper, we establish a hybrid FSO/RF testbed including an intensity modulation/direct detection (IM/DD) FSO subsystem with space diversity and a high-order quadrature amplitude modulation (QAM) RF subsystem with polarization diversity, respectively. Based on the testbed, we propose and experimentally validate an intelligent transmission system where the link selection and switching technology is implemented. In particular, we propose a gated recurrent unit (GRU) neural network enhanced by time attention mechanism for the hybrid system. The experimental results demonstrate that the proposed system can achieve the prediction of FSO channel fading with a high precision where absolute percentage error (APE) values lower than 3% account for up to 90% of the prediction results. The implemented intelligent hybrid system can significantly reduce the link switching frequency and link interruption duration. Then the BER is further verified on the testbed, and results show that the intelligent hybrid system can improve the BER from the order of 10−2 to the order of 10−3 during the time periods when link switching occurs.

Free Space Optical (FSO) communication has been widely studied because of its advantages such as rich spectrum resource, high transmission capacity, high security, low power consumption and flexible installation. However, FSO link is sensitive to weather conditions and atmospheric turbulence, which poses a great challenge on signal transmission quality. Differential Phase Shift Keying (DPSK) modulation is well recognized as a promising technique to deal with the inter-symbol interference due to channel fading. Nevertheless, the existing system structure for high-order DPSK modulation technology is too complex to be used in practice for FSO system. Therefore, this letter proposes a simplified DPSK modulation scheme. In order to alleviate signal transmission performance degradation caused by simplification, a constellation remapping method is employed in the proposed scheme to achieve flexible signal transmission and improve the Bit Error Rate (BER) performance. It is demonstrated that compared with the traditional DPSK system, the proposed scheme significantly reduces the system complexity and has better BER performance under low to moderate atmospheric turbulence.

Cooperative Free Space Optical (FSO) communication aims to combat atmospheric attenuation and turbulence by transmitting and receiving multiple copies of signal along different paths, and thus it relies on transmission redundancy. In this letter, we propose an asynchronous transmission scheme for cooperative FSO system. Different from the traditional cooperative FSO system with synchronous transmission, the source node in the proposed system can send different data to destination node. In order to recover the data of different links, a squared signal combination method is proposed and implemented at the receiver of destination. Therefore, compared to synchronous transmission, the asynchronous transmission not only brings diversity gain for cooperative FSO system, but also improves the channel utilization and thus the effective data rate. It is demonstrated that the Bit Error Rate (BER) of the asynchronous transmission is lower than that of the direct transmission and the synchronous transmission with equal data rate.

Spatial diversity is widely recognized as an effective technique for free-space optical (FSO) communication to combat channel fading. Most existing works on spatial diversity in FSO systems focus on intensity modulation and direct detection, while fewer mention coherent optical detection, which excels in optical receiver responsivity. Spatial diversity enables the FSO coherent system to demodulate the signal components of in-phase (I) and quadrature (Q) separately and thus simplify the coherent detector. More importantly, due to the differential channel conditions between I and Q components, we are offered a chance to realize an asymmetric quadrature amplitude modulation (QAM) constellation that can utilize the channel capacity of both I and Q components more sufficiently. Performance results demonstrate that the simplified structure and improved spectrum efficiency can be realized in the asymmetric QAM transmission system with an acceptable bit-error-rate loss.

Inhibitors of transcriptional protein–protein interactions (PPIs) have high value both as tools and for therapeutic applications. The PPI network mediated by the transcriptional coactivator Med25, for example, regulates stress-response and motility pathways, and dysregulation of the PPI networks contributes to oncogenesis and metastasis. The canonical transcription factor binding sites within Med25 are large (∼900 Å2) and have little topology, and thus, they do not present an array of attractive small-molecule binding sites for inhibitor discovery. Here we demonstrate that the depsidone natural product norstictic acid functions through an alternative binding site to block Med25–transcriptional activator PPIs in vitro and in cell culture. Norstictic acid targets a binding site comprising a highly dynamic loop flanking one canonical binding surface, and in doing so, it both orthosterically and allosterically alters Med25-driven transcription in a patient-derived model of triple-negative breast cancer. These results highlight the potential of Med25 as a therapeutic target as well as the inhibitor discovery opportunities presented by structurally dynamic loops within otherwise challenging proteins.

With the development of science, economy and society, the needs for research and exploration of deep space have entered a rapid and stable development stage. Deep Space Optical Network (DSON) is expected to become an important foundation and inevitable development trend of future deep-space communication. In this paper, we design a deep space node model which is capable of combining the space division multiplexing with frequency division multiplexing. Furthermore, we propose the directional flooding routing algorithm (DFRA) for DSON based on our node model. This scheme selectively forwards the data packets in the routing, so that the energy consumption can be reduced effectively because only a portion of nodes will participate the flooding routing. Simulation results show that, compared with traditional flooding routing algorithm (TFRA), the DFRA can avoid the non-directional and blind transmission. Therefore, the energy consumption in message routing will be reduced and the lifespan of DSON can also be prolonged effectively. Although the complexity of routing implementation is slightly increased compared with TFRA, the energy of nodes can be saved and the transmission rate is obviously improved in DFRA. Thus the overall performance of DSON can be significantly improved.

This paper proposes a new Energy-efficient Survivable Routing Protocol (ESRP) based on solar energy and wind mixed for power supply in green wireless mesh networks (WMNs). The ESRP combines hop penalty strategy and flooding delaying strategy to improve the performances of traditional routing protocol. This paper uses QualNet to simulate and verify the performances of proposed ESRP. Compared with the traditional routing protocol, the simulation results show that the energy utilization of ESRP is more efficient by 13%. At the same time, ESRP is more load-balanced to postpone the appearance of the first energy depletion node and reduce the number of energy depletion nodes, and thus it effectively improves network survivability.

Energy savings in Internet have been regarded as a significant technical issue for academic and industrial community. Particularly, access network accounts for more than 70% of the total energy consumption of Internet. As a promising access technique, Fiber-Wireless (FiWi) network not only enables the cost-effective broadband access, but also provides more opportunities for energy savings. Previous works mostly focused on the energy savings in the optical back-end of FiWi. Generally, they extended the Optical Network Unit (ONU) sleep mechanisms initially designed for Passive Optical Network (PON) to FiWi by combining with the wireless rerouting. However, most of these works left the energy savings in the wireless front-end untouched. In fact, when one or more ONUs in the network is/are sleeping, many wireless components remain idle or underutilized which cause a lot of energy waste. Motivated by this, we propose a new integrated Wireless-Optical Energy Savings (WOES) scheme for the comprehensive energy savings in FiWi. The WOES scheme consists of two interactive modules, Energy-Efficient ONU Management (EEOM) and Energy-Aware Topology Configuration (EATC). EEOM aims at the energy savings in the optical back-end by putting the low-load ONUs into sleep state. A pair of thresholds is introduced into EEOM to maintain the states of ONUs. As soon as ONUs states change, EATC will reconfigure the wireless topology by putting the idle Radio Interfaces (RIs) into standby state, thus minimizing the energy consumption of the wireless front-end. Simulation results show that the WOES scheme can reduce the energy consumption significantly with just a little performance degradation in network throughput and end-to-end delay.

The hybrid Wireless-Optical Broadband Access Network (WOBAN) provides a new and promising architecture for broadband access network by combining the beneficial properties of wireless and optical access technologies. To avoid huge data loss, WOBAN needs to be designed with a high availability guarantee. The purpose of this paper is to protect the Passive Optical Network at the back-end using the backup radios in Wireless Mesh Network at the front-end. The proposed protection scheme is based on a connection availability model. First, we assigned several backup Optical Network Units (ONUs) for each primary ONU not satisfying the availability requirement of primary optical connection. Under the availability requirement of backup optical connection, each backup ONU needed to reserve the residual capacity as the backup capacity to fully protect the traffic demand of its primary ONU. Then, we selectively deployed the additional radio interfaces as the backup radios for the wireless routers in the front-end under the availability requirement of backup wireless connection, in order to establish the wireless-backup-path between each pair of primary and backup ONUs. Each backup radio on the wireless-backup-path will retain the backup radio capacity for rerouting traffic, so as to decrease the possibility of traffic block in case of failure. We aimed to design efficient heuristic algorithms and yield suboptimal solutions for minimizing the consumption of backup ONU capacity and the cost of backup radios. Simulation results demonstrate the advantage of the proposed scheme compared to previous works.

Currently, multicast survivability in optical network obtains more attention. This paper focuses on the field of multicast grooming shared protection in green optical network and designs a novel auxiliary graph and a shared matrix to address the survivable multicast resource consumption. This paper also proposes a new heuristic called Green Multicast Grooming algorithm based on spanning path Cross-Shared protection (GMG-CSP), in which network reliability, energy efficiency and resource utilization are jointly considered. Simulation results testify that, compared to other algorithms, the proposed GMG-CSP not only has lower blocking probability and higher bandwidth utilization ratio, but also saves more energy.

Owing to the recent advancements in the Internet of Things (IoT), an increasing number of IoT devices have led to frequency crowding in wireless networks. The low-complexity visible light communication (VLC) system is a promising solution for indoor frequency-crowded wireless networks owing to the ubiquity of light-emitting diodes (LEDs) and readily deployable, low-cost modulation methods. However, due to the inherent limitations of LED materials and growth of data from IoT applications, low-complexity VLC systems can barely boost the data throughput without adding complex modulations and circuits. This study aims to design and implement a spectrum-efficient, low-complexity VLC system to improve data throughput with very little cost to support indoor IoT applications. This system uses multiamplitude voltage to transmit multiple bit streams simultaneously, making it a novel system. However, it is not trivial to achieve this goal as the varying voltage can cause the LEDs to flicker. Therefore, we further propose a voltage-to-current amplifier circuit, which effectively mitigates the effects of changes in the LED’s brightness upon human eyes. Finally, we evaluate the system under different speeds, distances, and angles. Extensive experiments demonstrate promising results from the viewpoint of spectrum efficiency, throughput, bit-error rate, and user perception.