The success of immune checkpoint blockade (ICB) promotes the immunotherapy to be a new pillar in cancer treatment. However, the low response rate of the ICB therapy limits its application. To increase the response rate and enhance efficacy, the ICB combination therapy has emerged and its clinical trials are increasing. Nevertheless, the gene expression profile and its pattern of ICB combination were not comprehensively studied, which limits the understanding of the ICB combination therapy and the identification of new drugs. Here, we constructed ICBcomb (http://bioinfo.life.hust.edu.cn/ICBcomb/), a comprehensive database, by analyzing the human and mouse expression data of the ICB combination therapy and comparing them between groups treated with ICB, other drugs or their combinations. ICBcomb contains 1399 samples across 29 cancer types involving 52 drugs. It provides a user-friendly web interface for demonstrating the results of the available comparisons in the ICB combination therapy datasets with five functional modules: [1, 2] the 'Dataset/Disease' modules for browsing the expression, enrichment and comparison results in each dataset or disease; [3] the 'Gene' module for inputting a gene symbol and displaying its expression and comparison results across datasets/diseases; [4] the 'Gene Set' module for GSVA/GSEA enrichment analysis on the built-in gene sets and the user-input gene sets in different comparisons; [5] the 'Immune Cell' module for immune cell infiltration comparison between different groups by immune cell abundance analysis. The ICBcomb database provides the first resource for gene expression profile and comparison in ICB combination therapy, which may provide clues for discovering the mechanism of effective combination strategies and new combinatory drugs.

In emergency scenarios, strong mobility and serious interference cause unstable transmission of on-site information such as close-up photos and high resolution videos, which requires a robust temporary communication network. In this paper, we focus on a UAV-assisted wireless cooperative communication and coded caching network, where emergency command vehicles and a UAV serve as content providers (CPs) to cache and transmit coded fragments or complete files for rescuers regarded as content requesters (CRs). The delivery success probability and content hit ratio are theoretically derived by incorporating the physical connectivity and social relationship between CPs and CRs. Aiming at maximizing the overall content hit ratio, we propose a multiagent two-timescale deep reinforcement learning (MA2T-DRL) algorithm to jointly optimize the transmission power and caching strategies for CPs. Specifically, we develop a two tier deep-Q networks (DQNs) framework integrating a slow-timescale DQN (ST-DQN) and a fast-timescale DQN (FT-DQN) for caching decision-making and power decision-making respectively, and then the QMIX framework is leveraged to aggregate all the outputs from local ST-DQNs. Considering the cooperative characteristics of coded caching, we further propose a novel clustering method for CPs such that CPs in the same cluster have the same willingness to serve CRs, and each cluster is regarded as the agent for training which further reduces the aggregation scale of the mixing network. Simulation results show that the proposed MA2T-DRL algorithm is efficient in model training, and presents the advantages in performance and complexity compared with the single-agent centralized training and the multiagent independent distributed training.

Persistent memory (PM) exhibits a huge potential to provide applications with a hybrid memory system where both DRAM and PM are directly connected to a CPU. In such a system, an efficient indexing data structure such as a persistent tree becomes an indispensable component. Designing a capable persistent tree, however, is challenging as it has to ensure consistency, persistence, and scalability without substantially degrading performance. Besides, it needs to prevent persistent memory leaks. While hash table has been widely used for main memory indexing due to its superior performance in random query, ART (Adaptive Radix Tree) is inherently better than B/B+-tree in most basic operations on both DRAM and PM. To exploit their complementary merits, in this paper we propose a novel concurrent and persistent tree called HART (Hashassisted ART), which employs a hash table to manage ARTs. HART employs a selective consistency/persistence mechanism and an enhanced persistent memory allocator, which can not only optimize its performance but also prevent persistent memory leaks. Experimental results show that in most cases HART significantly outperforms WOART and FPTree, two state-of-theart persistent trees. Also, it scales well in concurrent scenarios.

Existing in-storage processing (ISP) techniques mainly focus on maximizing data processing rate by always utilizing total storage data processing resources for all applications. We find that this "always running in full gear" strategy wastes energy for some applications with a low data processing complexity. In this paper we propose RISP (Reconfigurable ISP), an energy-aware reconfigurable ISP framework that employs FPGA as data processing cells and NVM controllers. It can reconfigure storage data processing resources to achieve a high energy-efficiency without any performance degradation for big data analysis applications. RISP is modeled and then validated on an FPGA board. Experimental results show that compared with traditional host-CPU based computing RISP (with 16 channels or more) improves performance by 1.6-25.4× while saving energy by a factor of 2.2-161. Further, its reconfigurability can provide up to 77.2% additional energy saving by judiciously enabling data processing resources that are sufficient for an application.

Existing persistent memory (PM) based file systems rely on a DRAM and PM hybrid store. Although a hybrid store does boost system performance while avoiding some current PM limitations like limited endurance, we envision that with more advances PM technologies could provide applications with a single-level persistent store in the not-so-distant future. As a first step to explore this direction, in this paper we design, implement, and evaluate a new persistent memory file system called SPFS (Single-level Persistent File System), which completely bypasses conventional DRAM-based volatile main memory. Unlike all existing PM-based file systems, SPFS never leverages DRAM to manage its metadata. Thus, redundant copies of metadata in volatile main memory (e.g., a copy of an inode in DRAM) and data movements between the two memories (e.g., copying an inode from PM to DRAM) can be totally eliminated. The goal of this paper is to explore how to manage files and their metadata with guaranteed data consistency on PM without the support of DRAM, which makes a first step towards the ultimate success of a single-level persistent store. Our experimental results demonstrate that SPFS outperforms traditional DRAM-based in-memory file systems ramfs and tmpfs in most cases. Besides, its performance is only moderately worse than that of NOVA, a state-of-the-art PM-based file system.

Simply applying an existing redundant array of independent disks (RAID) technique to enhance data reliability within a single solid-state drive for safety-critical mobile applications significantly degrades performance. In this article, we first propose a new RAID5 architecture called channel-RAID5 with mirroring (CR5M) to alleviate the performance degradation problem. Next, an associated data reconstruction strategy called mirroring-assisted channel-level reconstruction (MCR) is developed to further shrink the window of vulnerability. Experimental results demonstrate that compared with channel-RAID5 (CR5), CR5M improves performance up to 40.2%. Compared with disk-oriented reconstruction, a traditional data reconstruction scheme, MCR on average improves data recovery speed by 7.5% while delivering a similar performance during reconstruction.

Since little has been reported in the literature concerning enterprise storage system file-level request scheduling, we do not have enough knowledge about how various scheduling factors affect performance. Moreover, we are in lack of a good understanding on how to enhance request scheduling to adapt to the changing characteristics of workloads and hardware resources. To answer these questions, we first build a request scheduler prototype based on WAFL®, a mainstream file system running on numerous enterprise storage systems worldwide. Next, we use the prototype to quantitatively measure the impact of various scheduling configurations on performance on a NetApp®'s enterprise-class storage system. Several observations have been made. For example, we discover that in order to improve performance, the priority of write requests and non-preempted restarted requests should be boosted in some workloads. Inspired by these observations, we further propose two scheduling enhancement heuristics called SORD (size-oriented request dispatching) and QATS (queue-depth aware time slicing). Finally, we evaluate them by conducting a wide range of experiments using workloads generated by SPC-1 and SFS2014 on both HDD-based and all-flash platforms. Experimental results show that the combination of the two can noticeably reduce average request latency under some workloads.

Digital filters are widely used in signal processing and communication systems. In some cases, the reliability of those systems is critical, and fault tolerant filter implementations are needed. Over the years, many techniques that exploit the filters' structure and properties to achieve fault tolerance have been proposed. As technology scales, it enables more complex systems that incorporate many filters. In those complex systems, it is common that some of the filters operate in parallel, for example, by applying the same filter to different input signals. Recently, a simple technique that exploits the presence of parallel filters to achieve fault tolerance has been presented. In this brief, that idea is generalized to show that parallel filters can be protected using error correction codes (ECCs) in which each filter is the equivalent of a bit in a traditional ECC. This new scheme allows more efficient protection when the number of parallel filters is large. The technique is evaluated using a case study of parallel finite impulse response filters showing the effectiveness in terms of protection and implementation cost.

Manufacturers are continuously pushing NAND flash memory into smaller geometries and enforce each cell to store multiple bits in order to largely reduce its cost. Unfortunately, these scaling down techniques inherently degrade the endurance and reliability of flash memory. As a result, permanent errors such as block or die failures could occur with a higher possibility. While most transient errors like programming errors can be fixed by an ECC (error correction code) scheme, rectifying permanent errors requires a data redundancy mechanism like RAID (redundant array of independent disks) in a single SSD where multiple channels work in parallel. To enhance the reliability of a solid-state drive (SSD) while maintaining its performance, we first implement several common RAID structures in the channel level of a single SSD to understand their impact on an SSD's performance. Next, we propose a new data redundancy architecture called CR5M (Channel-RAID5 with Mirroring), which can be applied to one SSD for mission-critical applications. CR5M utilizes hidden mirror chips to accelerate the performance of small writes. Finally, we conduct extensive simulations using real-world traces and synthetic benchmarks on a validated simulator to evaluate CR5M. Experimental results demonstrate that compared with CR5 (Channel-RAID5) CR5M decreases mean response time by up to 25.8%. Besides, it reduces the average writes per channel by up to 23.6%.

An effective method is presented for position tracking of a moving mobile terminal (MT). The method is based on time/distance difference of arrival (TDOA) estimation and Doppler measurements. TDOA locationing based on Chan's method provides an analytical solution which is closer to the Cramer-Rao Lower Bound (CRLB).However its accuracy is affected by multi-access interferences and non-line-of-sight (NLOS), thus making Doppler-aided positioning a good complementary technique due to its independency of the above effects. After acquiring the initial position of MT using TDOA information, the moving track is estimated by a hybrid method which combines TDOA with Doppler. Simulation results show this hybrid method can achieve better performance than TDOA or Doppler technique.

A location method of the user equipment (UE) in distributed antenna system (DAS) is presented, which uses the technique of the velocity measurement based on Doppler frequency shift. The location equations are formed from Doppler shifts of remote antennas (RAUs). Due to the nonlinear nature of the problem, the solution must be found by the grid searching. However, when the error of the Doppler measurement is a Gauss random variable, the solution can be achieved easily by a two- dimension searching in orthogonal complement space, i.e. the search is only performed in a two-dimension space (the position space) instead of the normal four-dimension space (both the position and the velocity spaces). Simulation results show that the proposed method can approach to a high precise of the UE location.

In this paper, a two-layer code division multiple access (CDMA) hierarchical cellular network structure is presented, which made up underlaid distributed antenna system (DAS) and overlaid macrocells. The analysis of coverage characteristic shows that embedding DAS instead of microcells in the macrocell makes network control and site engineering easier to be performed. Signal to interference ratio (SIR) of the macrocell/DAS is studied and compared with that of the macrocell/microcell system. Remote access unit (RAU) selection is employed to reduce the interference from the forward link in DAS. Simulation results show that performance of macrocell/DAS is superior to that of macrocell/microcell in the CDMA hierarchical system.