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As a key component of high‐performance switches and routers, the packet forwarding engine (PFE) is mainly responsible for selecting the appropriate output port for tens of thousands of packets within an extremely short time frame. However, the performance of PFE is determined by the selected group membership algorithm. This paper puts forth a hybrid strategy–caching scalar‐pair and vectors routing and forwarding (CSVRF), consisting of virtual output port bitmap caching (VOPBC) and fractional‐N SVRF to address major multicast forwarding issues such as scalability by using content addressable memory. In CSVRF, a virtual output port bitmap cache is introduced, which includes the most popular combinations of output port bitmap and divides the big scalar‐pair into N sub‐groups to achieve parallel compute and the reusability of less bit‐length prime. The results demonstrate that the memory space and the forwarding latency are effectively reduced compared with previous work. In space efficiency, it only required 10% memory space compared with the original SVRF/fractional‐N SVRF, decreased 10% memory usage compared with pure VOPBC and nearly improved 1 to 4 orders of magnitude of packet processing time compared with the original SVRF and the fractional‐N SVRF respectively. [ABSTRACT FROM AUTHOR]

With the development of mobile edge computing technology, edge caching provides a feasible solution for low‐latency and high‐reliability data forwarding in the Internet of Vehicles (IoV). Due to the limited number and storage capacity of the edge servers, and the limited communication range of a single vehicle, the delay and connection requirements are hard to be satisfied. A vehicle clustering based edge caching scheme is proposed in this paper, aiming at minimizing the content acquisition delay of the requesting vehicles (RVs) within the communication range of the edge servers. After getting the optimal vehicle association results, the minimization of content acquisition delay is transformed into a knapsack problem, which is then solved by a dynamic programming algorithm to obtain the optimal cache decisions. Simulation results show that the proposed scheme reduces task acquisition delay by at least about 100 s and increases the cache hit rate by about 50%, compared with the random cache scheme. [ABSTRACT FROM AUTHOR]

Parallel global optimization of expensive simulation models like nonlinear partial differential equations (PDEs) can speed up model calibration or project design decisions, but the impact of memory management on the efficiency of using parallel global optimization methods has not been previously studied. This paper quantifies cache memory limitations arising during parallel optimization of expensive PDE models. An efficient parallel optimization algorithm is applied to model calibration for two different, expensive real‐world PDEs (i.e., hydrodynamic and water quality analysis for a 250‐hectare lake). One of these two lake models takes 4.5 h per simulation in serial, but that PDE simulation time per simulation increases to 12 h with parallel optimization if default processor scheduling strategy is used on a modern nonuniform memory access multicore platform. We proposed a novel mixed affinity scheduling strategy for parallel simulation optimization that increases computational efficiency by as much as 20% over the default affinity strategy. [ABSTRACT FROM AUTHOR]

MapReduce is a framework that can process huge datasets in parallel and distributed computing environments. However, a single machine failure during the runtime of MapReduce tasks can increase completion time by 50%. MapReduce handles task failures by restarting the failed task and re‐computing all input data from scratch, regardless of how much data had already been processed. To solve this issue, we need the computed key‐value pairs to persist in a storage system to avoid re‐computing them during the restarting process. In this paper, the task failure resilience (TFR) technique is proposed, which allows the execution of a failed task to continue from the point it was interrupted without having to redo all the work. Amazon ElastiCache for Redis is used as a non‐volatile cache for the key‐value pairs. We measured the performance of TFR by running different Hadoop benchmarking suites. TFR was implemented using the Hadoop software framework, and the experimental results showed significant performance improvements when compared with the performance of the default Hadoop implementation. [ABSTRACT FROM AUTHOR]

Uncore components such as on‐chip memory systems and on‐chip interconnects consume a large amount of energy in emerging embedded applications. Few studies have focused on next‐generation analytical models for future chip‐multiprocessors (CMPs) that simultaneously consider the impacts of the power consumption of core and uncore components. In this paper, we propose a convex‐optimization approach to design heterogeneous uncore architectures for embedded CMPs. Our convex approach optimizes the number and placement of memory banks with different technologies on the memory layer. In parallel with hybrid memory architecting, optimizing the number and placement of through silicon vias as a viable solution in building three‐dimensional (3D) CMPs is another important target of the proposed approach. Experimental results show that the proposed method outperforms 3D CMP designs with hybrid and traditional memory architectures in terms of both energy delay products (EDPs) and performance parameters. The proposed method improves the EDPs by an average of about 43% compared with SRAM design. In addition, it improves the throughput by about 7% compared with dynamic RAM (DRAM) design. [ABSTRACT FROM AUTHOR]

File systems and applications try to implement their own update protocols to guarantee data consistency, which is one of the most crucial aspects of computing systems. However, we found that the storage devices are substantially under-utilized when preserving data consistency because they generate massive storage write traffic with many disk cache flush operations and force-unit-access ( FUA) commands. In this paper, we present DJFS (Delta-Journaling File System) that provides both a high level of performance and data consistency for different applications. We made three technical contributions to achieve our goal. First, to remove all storage accesses with disk cache flush operations and FUA commands, DJFS uses small-sized NVRAM for a file system journal. Second, to reduce the access latency and space requirements of NVRAM, DJFS attempts to journal compress the differences in the modified blocks. Finally, to relieve explicit checkpointing overhead, DJFS aggressively reflects the checkpoint transactions to file system area in the unit of the specified region. Our evaluation on TPC-C SQLite benchmark shows that, using our novel optimization schemes, DJFS outperforms Ext4 by up to 64.2 times with only 128 MB of NVRAM. [ABSTRACT FROM AUTHOR]

State-of-the-art processors require increasingly complicated memory services for high performance and low power consumption. In particular, they request transfers within a burst in a wrap-around order to minimize the miss penalty of a cache. However, synchronous dynamic random access memories (SDRAMs) do not always generate transfers in the wrapround order required by the processors. Thus, a memory subsystem rearranges the SDRAM transfers in the wraparound order, but the rearrangement process may increase memory latency and waste the bandwidth of onchip interconnects. In this paper, we present a memory subsystem that is effective for the wrapping bursts of a cache. The proposed memory subsystem makes SDRAMs generate transfers in an intermediate order, where the transfers are rearranged in the wrap-around order with minimal penalties. Then, the transfers are delivered with priority, depending on the program locality in space. Experimental results showed that the proposed memory subsystem minimizes the memory performance loss resulting from wrapping bursts and, thus, improves program execution time. [ABSTRACT FROM AUTHOR]

Cache‐enabled device‐to‐device (D2D) network has been deemed as an effective technique to offload the data traffic. However, the gain of the caching schemes is closely related to the homogeneity among users' preference distribution. To tackle this issue, recommendation is a promising proactive approach. It increases the request probability of recommended contents, reshaping users' contents demand patterns, and improving caching performance. Moreover, considering the heterogeneous network settings, i.e. content retrieval costs vary, the routing design becomes a non‐negligible factor on caching performance optimization. On these grounds, the average system cost of D2D‐enabled wireless caching networks with multiple BSs is first described. Then the routing strategies are designed together with caching and recommendation policies by minimizing the average cost of these networks. The optimization problem is proven as NP‐hard. To facilitate the analysis, the original problem is decoupled into two sub‐problems and solve them respectively. Afterwards, all the variables are optimized in an alternating manner until the convergence is achieved. The proposed algorithm's convergence performance and benefits over benchmark strategies in terms of total cost and cache hit ratio are supported by Monte‐Carlo simulation results. [ABSTRACT FROM AUTHOR]

The authors consider the effect of caching in interference-limited wireless networks where fading is the dominant channel effect. First, the authors propose a one-hop transmission strategy for cache-enabled wireless networks, which is based on exploiting multi-user diversity gain. Then, they derive a closed-form result for throughput scaling of the proposed scheme in large networks, which reveals the inherent trade-off between cache memory size and network throughput. Their results show that substantial throughput improvements are achievable in networks with sources equipped with large cache size, compared with previous works where each transmitter could just store one file. Also, the authors provide extensive simulations through which they analyse network throughput and verify their analytical results. Their simulations suggest that the scaling results also hold true even by introducing correlation between channels, making the results more general. [ABSTRACT FROM AUTHOR]

In current NAND flash design, one of the most challenging issues is reducing peak current consumption (peak ICC), as it leads to peak power drop, which can cause malfunctions in NAND flash memory. This paper presents an efficient approach for reducing the peak ICC of the cache program in NAND flash memory -- namely, a program Cache Busy Time (tPCBSY) control method. The proposed tPCBSY control method is based on the interesting observation that the array program current (ICC2) is mainly decided by the bit-line bias condition. In the proposed approach, when peak ICC2 becomes larger than a threshold value, which is determined by a cache loop number, cache data cannot be loaded to the cache buffer (CB). On the other hand, when peak ICC2 is smaller than the threshold level, cache data can be loaded to the CB. As a result, the peak ICC of the cache program is reduced by 32% at the least significant bit page and by 15% at the most significant bit page. In addition, the program throughput reaches 20 MB/s in multiplane cache program operation, without restrictions caused by a drop in peak power due to cache program operations in a solid-state drive. [ABSTRACT FROM AUTHOR]

The development of the Internet of things brings exponential growth of wireless traffic, which puts great pressure on the backhaul link. The proactive caching of some contents in the edge device of mobile network can effectively reduce the repeated transmission of the same contents and relieve the burden of the backhaul link. Moreover, the introduction of recommendation mechanisms can reshape user's request and improve cache hit ratio. However, the optimization of recommendation and caching decisions is highly dependent on the users' preference information for files. Here, a joint optimization algorithm of recommendation and caching based on users' preference prediction with multiple base stations cooperative caching is proposed. To improve the caching efficiency, the Deep Crossing model is adopted to predict users' preferences. Under the constraints of cache capacity, recommendation quantity and bandwidth, an optimization problem to minimize the total transmission delay of the system is formulated. Then, the NP‐hardness of the proposed optimization problem is proved and it is decoupled it into three sub‐problems, namely recommendation, user access and caching optimization sub‐problems. Simulation results show that the proposed algorithm can effectively reduce the total transmission delay of the system. we propose a joint optimization algorithm of recommendation and caching based on users' preference prediction with multiple base stations cooperative caching. To improve the caching efficiency, we adopt the Deep Crossing model to predict users' preferences. Under the constraints of cache capacity, recommendation quantity and bandwidth, we formulate an optimization problem to minimize the total transmission delay of the system. [ABSTRACT FROM AUTHOR]

In this study, the caching problem is investigated. Assuming that the users are only equipped with buffer of small sizes, the peak rate of caching problem is investigated in this study. In contrast to recent results in the literature, this study shows that under some specific condition, i.e. if the number of users is no less than the amount of files in the server, a lower peak rate of caching is achievable. Furthermore, this new presented peak rate of caching is demonstrated to coincide with the well-known cut-set bound. [ABSTRACT FROM AUTHOR]

In general, it is accepted that gap formation significantly affects the placement of scatter‐hoarded seeds by small rodents, but the effects of different forest gap sizes on the seed‐eating and scatter‐hoarding behaviors of small rodents remain unclear. Thus, we examined the effects of a closed‐canopy forest, forest edge, and gaps with different sizes on the spatial dispersal of Quercus variabilis acorns and cache placement by small rodents using coded plastic tags in the Taihang Mountains, China. The seeds were removed rapidly, and there were significant differences in the seed‐eating and caching strategies between the stand types. We found that Q. variabilis acorns were usually eaten after being removed from the closed‐canopy forest and forest edges. By contrast, the Q. variabilis acorns in the forest gap stands were more likely to be scatter‐hoarded. The dispersal distances of Q. variabilis acorns were significantly longer in the forest gap plots compared with the closed canopy and forest edge plots. However, the proportion of scatter‐hoarded seeds did not increase significantly as the gap size increased. In small‐scale oak reforestation projects or research, creating small gaps to promote rodent‐mediated seed dispersal may effectively accelerate forest recovery and successional processes. [ABSTRACT FROM AUTHOR]

With the growth of mobile data traffic in wireless networks, caches are used to bring data closer to mobile users and to minimise the traffic load on macro base station (MBS). Storing data in caches on user terminals (UTs) and small base stations (SBSs) faces challenges with respect to the decision of cache contents. Here, a multi‐objective cache content strategy that aims to maximise the cache hit rate of SBSs in mobile edge networks (MENs) is proposed. The multi‐objective cache placement optimisation is formulated as a classification problem. Unlike previous work, mobility input attributes such as user locations, contact duration, communication ranges, contact probability between UTs and SBSs, etc. as well as content popularity and the correlation between these input attributes separating the decision space into two regions of cache and not cache are used. Stochastic gradient descent algorithm is used for the training of three supervised machine learning techniques: artificial neural network ANN, support vector machine (SVM), and logistic regression LR to define the hyperplane that separates the cache content decision space. Simulation results show that compared with the weighted‐sum approach, the SBSs cache hit rates increase on the average by 18.58%, 18.52%, and 18.2%, and the total energy consumption values decrease on the average by 33.49%, 53.19%, and 49.9% for ANN, SVM, and LR, respectively. [ABSTRACT FROM AUTHOR]

To solve the inefficient use of internet protocol (IP) addresses in the current host‐centric internet, the content‐centric networking (CCN) replaces the IP address with the content name and the cache memory is used to store data temporarily on each router. One of the key components in CCN is the pending interest table (PIT). When an interest arrives at a CCN node, the node searches the PIT entries for the same request. If no, the node searches the PIT for an idle entry and a request is sent. If there is no idle entry, the request is blocked. If yes, the aggregation mechanism is performed. To prevent the request from becoming out‐of‐date, the timeout mechanism is adopted. In this work, the authors focus on the performance analysis of PIT in the cellular network with two classes of interests, new and handoff interests. To provide service differentiation, a reservation mechanism is adopted. Furthermore, interests may enter the retrial queue and wait to retry later. First, the authors derived the analytical model for the system considered. Second, the impact of various system parameters on the performance measures is studied. Last but not least, computer simulation is written to verify the accuracy of the analytical results. [ABSTRACT FROM AUTHOR]

Current approaches to information-centric network (ICN) implementation employ the edge storage of network infrastructures to minimise the latency of information retrieval. However, the edge storage of infrastructures is finite. Distributed content caching assisted by mobile devices becomes a potential solution to content publishing services. Nevertheless, under the conventional half-duplex-based ICN, extra memory is occupied and the delay is increased. Fortunately, full duplex (FD) communications can improve the spectrum efficiency of wireless networks, and reduce the access delay by more flexible content caching. In this study, the authors propose a novel FD-based ICN (FD-ICN) framework, where content caching is not only implemented in network infrastructures but also in mobile devices. Content cached by mobile devices can be delivered in a FD amplify and forward way without extra BS memory occupation and delay. To maximise the network utility of the FD-ICN, they formulate the caching strategy and FD radio resource allocation as a joint optimisation problem. A joint caching strategy and FD radio resource allocation algorithm are proposed. Simulation results show their FD-ICN framework can achieve superior system utility compared to the conventional ICN. Moreover, the proposed algorithm exhibits higher utility with similar converge rate compared to the heuristic algorithm. [ABSTRACT FROM AUTHOR]

Caching at the user devices is a key technology to alleviate backhaul load and improve users' quality of experience in mobile edge networks. However, due to the concern of privacy and limited battery life, users are not willing to share their resources. In this study, the authors jointly design the caching strategy and incentive scheme to encourage the users to share their storage resources and improve the social welfare of the cellular network. First, the user equipments (UEs) are classified into different types according to their preference to share cache resources. Then, based on contract theory, an optimisation problem with necessary constraints is formulated aiming at maximising the base station (BS)'s utility. The reward the BS pays for a UE is based on the total amount of contents it shares with other UEs, which is related to the caching policy of UEs. A heuristic caching strategy is proposed and the optimal contract is obtained. Finally, the system performance of the proposed solution is analysed, simulation results show that the incentive scheme can improve the willingness of users to share contents, and the proposed caching strategy contributes more to the social welfare compared with two baseline caching schemes: fair caching and random caching. [ABSTRACT FROM AUTHOR]

An effective design of cache memory is an important aspect in computer architecture to improve the system performance. In this work, we study the effect of reducing the cache comparisons to map the cache address on the performance experimentally and analytically. Cache miss penalties have drastic impact on the systems' performance. To overcome this, we propose a novel tag access scheme, which uses a partial comparison unit called n‐bit comparator and use multiple search methods inside the data cache to improve the cache performance by reducing cache access time. Partial tag comparison (PTC) enables the cache to compare the tag in multi‐stage techniques starting with the least significant bits (LSBs). Thus, useless tag comparison and number of tag bits being compared can be effectively reduced, hence reaching the requested tag is faster and the cache hit time is reduced. Simulation results show that the proposed approach outperforms conventional mapping techniques. The PTC technique improves the hit time in 2‐bank and 4‐bank fully associative caches by 70–96% and 67–88% over a cache with full tag comparison. Moreover, the proposed technique provides the minimum hit time when using a hash searching method rather than other searching methods: linear and binary. [ABSTRACT FROM AUTHOR]

The last decade has recorded an increase in security protocols for integrated circuits and memory systems, because of device specific attacks such as side‐channel monitoring and cold boot and also because sensitive information is stored in such devices. The scope of this study is to propose new security measures which can be applied in memory systems, in order to make the stored data unusable, if retrieved successfully by any type of attack. The security technique uses interleaved scrambling vectors to scramble the data retained in a memory system and employs several dissemination rules. The proposed technique is investigated and assessed from several perspectives, such as power consumption, time performance and area overhead. [ABSTRACT FROM AUTHOR]