To achieve precise measurement without landing, the high-mobility vehicle-mounted theodolite needs to be leveled quickly with high precision and ensure sufficient support stability before work. After the measurement, it is also necessary to ensure that the high-mobility vehicle-mounted theodolite can be quickly withdrawn. Therefore, this paper proposes a hierarchical automatic leveling strategy and establishes a two-stage electromechanical automatic leveling mechanism model. Using coarse leveling of the first-stage automatic leveling mechanism and fine leveling of the second-stage automatic leveling mechanism, the model realizes high-precision and fast leveling of the vehicle-mounted theodolites. Then, the leveling control method based on repeated positioning is proposed for the first-stage automatic leveling mechanism. To realize the rapid withdrawal for high-mobility vehicle-mounted theodolites, the method ensures the coincidence of spatial movement paths when the structural parts are unfolded and withdrawn. Next, the leg static balance equation is constructed in the leveling state, and the support force detection method is discussed in realizing the stable support for vehicle-mounted theodolites. Furthermore, a mathematical model for “false leg” detection is established furtherly, and a “false leg” detection scheme based on the support force detection method is analyzed to significantly improve the support stability of vehicle-mounted theodolites. Finally, an experimental platform is constructed to perform the performance test for automatic leveling mechanisms. The experimental results show that the leveling accuracy of established two-stage electromechanical automatic leveling mechanism can reach 3.6″, and the leveling time is no more than 2 mins. The maximum support force error of the support force detection method is less than 15%, and the average support force error is less than 10%. In contrast, the maximum support force error of the drive motor torque detection method reaches 80.12%, and its leg support stability is much less than the support force detection method. The model and analysis method proposed in this paper can also be used for vehicle-mounted radar, vehicle-mounted laser measurement devices, vehicle-mounted artillery launchers and other types of vehicle-mounted equipment with high-precision and high-mobility working requirements.

At manufacturing sites, mass customization is expanding along with the increasing variety of customer needs. This situation leads to complications in production planning for the factory manager, and production plans are likely to change suddenly at the manufacturing site. Because such sudden fluctuations in production often occur, it is particularly difficult to optimize the parts supply operations in these production processes. As a solution to such problems, Industry 4.0 has expanded to promote the use of digital technologies at manufacturing sites; however, these solutions can be expensive and time-consuming to introduce. Therefore, not all factory managers are favorable toward introducing digital technology. In this study, we propose a method to support parts supply operations that decreases work stagnation and fluctuation without relying on the experience of workers who supply parts in the various production processes. Furthermore, we constructed a system that is inexpensive and easy to introduce using both LPWA and BLE communications. The purpose of the system is to level out work in in-process logistics. In an experiment, the proposed method was introduced to a manufacturing site, and we compared how the workload of the site's workers changed. The experimental results show that the proposed method is effective for workload leveling in parts supply operations.

In this letter, we propose a static wear leveling technique, called Recency-based Wear Leveling (RbWL). The basic idea of RbWL is to execute static wear leveling at minimum levels, because the frequent migrations of cold data by static wear leveling cause significant overhead in a NAND flash memory system. RbWL adjusts the execution frequency according to a threshold value that reflects the lifetime difference of the hot/cold blocks and the total lifetime of the NAND flash memory system. The evaluation results show that RbWL improves the lifetime of NAND flash memory systems by 52%, and it also reduces the overhead of wear leveling from 8% to 42% and from 13% to 51%, in terms of the number of erase operations and the number of page migrations of valid pages, respectively, compared with other algorithms.

In this letter, we propose a round robin-based wear leveling (RRWL) for flash memory systems. RRWL uses a block erase table (BET), which is composed of a bit array and saves the erasure histories of blocks. BET can use one-to-one mode to increase the performance of wear leveling or one-to-many mode to reduce memory consumption. However, one-to-many mode decreases the accuracy of cold block information, which results in the lifetime degradation of flash memory. To solve this problem, RRWL consistently uses one-to-one mode based on round robin method to increase the accuracy of cold block identification, with reduced memory size of BET, like in one-to-many mode. Experiments show that RRWL increases the lifetime of flash memory by up to 47% and 14%, compared with BET and HaWL, respectively.

In this letter, we propose a garbage collection technique for non-volatile memory systems, called Migration Cost Sensitive Garbage Collection (MCSGC). Considering the migration overhead from selecting victim blocks, MCSGC increases the lifetime of memory systems and improves response time in garbage collection. Additionally, the proposed algorithm also improves the efficiency of garbage collection by separating cold data from hot data in valid pages. In the experimental evaluation, we show that MCSGC yields up to a 82% improvement in lifetime prolongation, compared with existing garbage collection, and it also reduces erase and migration operations by up to 30% and 29%, respectively.

In this letter, we propose a novel wear leveling technique we call Hidden cold block-aware Wear Leveling (HaWL) using a bit-set threshold. HaWL prolongs the lifetime of flash memory devices by using a bit array table in wear leveling. The bit array table saves the histories of block erasures for a period and distinguishes cold blocks from all blocks. In addition, HaWL can reduce the size of the bit array table by using a one-to-many mode, where one bit is related to many blocks. Moreover, to prevent degradation of wear leveling in the one-to-many mode, HaWL uses bit-set threshold (BST) and increases the accuracy of the cold block information. The performance results illustrate that HaWL prolongs the lifetime of flash memory by up to 48% compared with previous wear leveling techniques in our experiments.

The wear leveling is a critical factor which significantly impacts the lifetime and the performance of flash storage systems. To extend lifespan and reduce memory requirements, this paper proposed an efficient wear leveling without substantially increasing overhead and without modifying Flash Translation Layer (FTL) for huge-capacity flash storage systems, which is based on selective replacement. Experimental results show that our design levels the wear of different physical blocks with limited system overhead compared with previous algorithms.

We propose a new effective method of managing flash memory space for flash memory-specific file systems based on a log-structured file system. Flash memory has attractive features such as non-volatility and fast I/O speed, but it also suffers from inability to update in situ and from limited usage (erase) cycles. These drawbacks necessitate a number of changes to conventional storage (file) management techniques. Our focus is on lowering cleaning cost and evenly utilizing flash memory cells while maintaining a balance between these two often-conflicting goals. The proposed cleaning method performs well especially when storage utilization and the degree of locality are high. The cleaning efficiency is enhanced by dynamically separating cold data and non-cold data, which is called 'collection operation.' The second goal, that of cycle-leveling, is achieved to the degree that the maximum difference between erase cycles is below the error range of the hardware. Experimental results show that the proposed technique provides sufficient performance for reliable flash storage systems.

This paper deals with a new low-power clocking scheme for dynamic logic circuits to reduce power dissipation. Although conventional clocking schemes for dynamic logic circuits are mainly used for high-speed applications like domino circuits, their peak-current are very large due to the concentration of precharging and discharging in a short period. It is hard for these schemes to accomplish both reductions of power dissipation and high performance at the same time. In the field of power engineering, leveling power means decreasing peak-to-peak of power keeping its amount. So, we propose a sophisticated clocking scheme leveling power dissipation of processing elements that mainly reduces power dissipation of clock drivers. Our proposed clocking scheme uses an over-lapped clock with a fine-grain power control, and peak-current becomes lower and power dissipation in short period is leveled without penalty of speed performance. Our proposed scheme is applied to a 4-bit array multiplier, and reductions of power dissipation of both the multiplier and clock driver are measured by the HSPICE simulator based on 0.5 µm CMOS technology. It is shown that power dissipation of clock drivers, 4-bit array multiplier, and the total are reduced by about 13.2 percent, 2.6 percent and 7.0 percent, respectively. As a result, our clocking scheme is effective in reduction of power dissipations of clock drivers.

Demand for power in Japan has been increasing year by year, and steep demand is projected during daily peak load periods: particularly in summer, due to growing demand for air conditioning. This has resulted in a large gap between day and night demand for power. The daily and seasonal regularity of this demand gap is placing pressure on power utilities to reduce service costs and create a more dependable power supply. This study demonstrates the feasibility of an energy storage system for load leveling based on the electric double-layer capacitor (EDLC). This device is safer, has a longer service life and needs far less maintenance than the secondary cell. The system works to store surplus energy from a commercial AC line in an EDLC bank during the night, and release this energy for use during the daytime peak load period, using a novel interface circuit. This paper focuses in particular on the working principles and experimental results of the interface circuit, which comprises a voltage control oscillator (VCO), a bi-directional DC/DC converter, a bi- directional inverter, and a coupling inductor. The whole circuit is subjected to PLL control, so that automatic connection between DC from an EDLC bank and AC from a commercial power line may take place in a simpler, more reliable and less costly manner. The system allows for energy transfer on the basis of DC voltage as if electric charging and discharging had taken place in a full DC system.

Initial leveling of strapdown inertial navigation system is a prerequisite work for distinguishing between gravity and acceleration effects in the accelerometer sensing's. This study presents an on-line methodology to resolve the initial leveling problem of a vehicle, which is subject to a large, long duration, and abrupt disturbance input with a deterministic nature under noisy circumstances. The developed method herein is the Kalman filter based scheme with a robust input estimator, generalized M estimator, and a testing criterion. The generalized M estimator identifies the unexpected disturbance inputs in real time. In addition, hypothetical testing based on the least-squares estimator is devised to detect the input's onset and presence. A required regression equation between the observed value of the residual sequence with an unknown input and theoretical residual sequence of the Kalman filter with no input is formulated. Input estimation and detection are then provided on the basis of the derived regression equation. Moreover, Monte Carlo simulations are performed to assess the superior capabilities of the proposed method in term of rapid responses, accuracy, and robustness. The efficient initial leveling can facilitate the entire alignment of the inertial system.