Counter Value Research Articles

The validity of two Omron pedometers during treadmill walking is speed dependent

The purpose of this study was to examine the effects of walking speed on the accuracy of measurement of steps, distance, and energy expenditure of two commercially available Omron pedometers [HJ-720IT-E2 (HJ-720) and HJ-113-E (HJ-113)]. Twenty-four untrained males (age, 22.7 ± 2.8 years; BMI, 24.38 ± 2.19 kg m(-2); body fat (%), 16 ± 2.2; VO(2max), 40.2 ± 6.5 ml kg(-1) min(-1)) and 18 females (age, 22.4 ± 2.9 years; BMI, 21.68 ± 2.43 kg m(-2); body fat (%), 23% ± 1.8; VO(2max), 35.9 ± 2.8 ml kg(-1) min(-1)) walked at five different velocities (54, 67, 80, 94 and 107 m min(-1)) on a treadmill in 5-min stages while wearing three types of pedometers: (a) HJ-720, (b) HJ-113, and (c) Yamax Digi-Walker SW-200 (YAM). Step-count for each pedometer was recorded at the end of each stage and compared with the value of a hand counter. Additionally, Omron pedometers were evaluated on their distance and energy expenditure (against VO(2) measurement with a gas-exchange analyzer) accuracy during each stage. HJ-720 and HJ-113 demonstrated high accuracy (r = 0.80-0.99) at all speeds. YAM underestimated step-count only at 54 m min(-1) (r = 0.46). HJ-720 and HJ-113 overestimated distance at slower speeds and underestimated distance at faster speeds, providing mean distance values that where to within 1.5-4% at 80 m min(-1). HJ-720 and HJ-113 underestimated energy expenditure (gross kilocalories) by 28%, when compared to indirect calorimetry. These results suggest that although the Omron HJ-720 and HJ-113 pedometers are accurate in the measurement of step-count, they demonstrate limited accuracy in the assessment of traveled distance and energy expenditure in a speed-dependent manner.

Threshold-based Message Copies Control in Delay Tolerant Networks

Delay T olerant N etworks (DTN) generally lack end-to-end connectivity and multiple message copies routing protocols are often used to improve the efficiency that messages are delivered successfully, but network load is increased due to a large number of message copies. A new scheme based on threshold is presented to control message copies efficiently in the network s . A contact counter is added in e very node for Epidemic routing scheme and the counter of every node records the number of nodes , which it contacts, with the same copy for a message. If the counter value of a node reaches the threshold which was set , then the node drop s message copy. We analysis threshold in theory and derive the lower bound of threshold in delay tolerant networks . According to the lower bound of threshold, we can set a proper threshold in the networks . Using the new scheme message copies reduce obviously and are dropp ed completely in the end . The successful delivery ratio is no less than Epidemic routing and message copies are controlled efficiently. We show that it is validity in our scheme by comparing with the trends of message copies among different thresholds in two mobility scenes.

New Trust Based Security Approach for Ad-Hoc Networks

Secure routing is the milestone in mobile ad hoc networks. Ad hoc networks are widely used in military and other scientific areas with nodes which can move arbitrarily and connect to any nodes at will, it is impossible for Ad hoc network to own a fixed infrastructure. It also has a certain number of characteristics which make the security difficult. Routing is always the most significant part for any networks. We design a trust based packet forwarding scheme for detecting and isolating the malicious nodes using the routing layer information. This paper gives an overview about trust in MANETs and current research in routing on the basis of trust. It uses trust values to favor packet forwarding by maintaining a trust counter for each node. A node will be punished or rewarded by decreasing or increasing the trust counter. If the trust counter value falls below a trust threshold, the corresponding intermediate node is marked as malicious.

Impact of source counter on routing performance in resource constrained DTNs

We study routing schemes for Disruption Tolerant Networks (DTNs) where transmission bandwidth is scarce. In such a setting, a key issue is how to schedule the transmission of packets under limited bandwidth to optimize performance. Such a scheduling consists of source control (i.e., source nodes choosing a routing scheme) and the local transmission scheduling performed by each node. Existing works typically focus on transmission scheduling and buffer management aspects, but due to theoretical and practical difficulties, only heuristics have been proposed. In this work, we explore an alternative way to improve DTN routing performance via source control. We first show through simulation that for spray-and-wait routing scheme where the source node specifies the maximum allowed number of copies of a packet in the network, there exists an optimal counter value that achieves the minimum network-wide average packet delivery delay. Then as a first step towards understanding multi-hop multi-copy DTN routing schemes such as spray-and-wait scheme, we perform modeling study of two-hop single-copy scheme and two-hop multi-copy scheme under various transmission scheduling schemes, via queuing network analysis and continuous time Markov chain model analysis. Our modeling analysis provides insights into the impact of source counter on routing performance and further suggests the existence of an optimal counter value. Relying on the insights gained via simulations and modeling studies, we propose an adaptive scheme where nodes adjust their counter values to achieve minimum packet delivery delay, in a distributed and asynchronous fashion. Simulations demonstrate the effectiveness of our scheme and suggest the potential of exploring this rich area for improving DTN routing performance.

Development of a time‐synchronized wireless sensor network

AbstractNetwork‐based wireless sensing has become an important area of research and various new applications for remote sensing are expected to emerge. One of the promising applications is structural health monitoring of buildings or civil engineering structures, which often requires vibration measurement. For vibration measurement via a wireless network, time synchronization is indispensable. In this paper we introduce a newly developed time‐synchronized wireless sensor network system. The system employs an IEEE 802.11 standard‐based TSF counter and sends the measured data with the counter value. It makes possible consistency on a common clock among different wireless nodes. We describe the accuracy evaluation by simulation studies as the size of the nodes is increased. The hardware and software specifications of the developed wireless system are presented. The experiments were conducted in a three‐story reinforced concrete building and the results showed that the system performance significantly exceeds requirements. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 173(4): 46–53, 2010; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21020

On the universe, disjointness, and containment problems for simple machines

consider counter machines, which are nondeterministic one-way finite automata augmented with one counter, where at each step the counter can be incremented by 1, decremented by 1, or left unchanged, and can be tested for zero. Acceptance is by accepting state. We show that there is a fixed nondeterministic real-time (i.e., no ϵ -move) 1-reversal counter machine A (once the counter decrements it can no longer increment) such that it is undecidable to determine, given an arbitrary positive integer d, whether A d (which is A with initial counter value d) accepts all strings. then strengthen the above result by showing that it also holds when A’s counter is partially blind in that it cannot be tested for zero (the machine aborts when there is an attempt to decrement the counter when it is zero), and the only condition for acceptance is for the counter to be zero when the input head falls off the right end of the input. We assume that on every input x for which d ⩾ | x | , the counter is initially set to | x | . (We make this assumption since, otherwise, A d cannot be both real-time and satisfy the zero-counter requirement for acceptance.) We also prove a similar result for partially blind 2-head nondeterministic finite automata. ally, we sharpen the well-known results that the disjointness and containment problems for deterministic pushdown automata are undecidable.

Model checking memoryful linear-time logics over one-counter automata

We study complexity of the model-checking problems for LTL with registers (also known as freeze LTL and written LTL ↓ ) and for first-order logic with data equality tests (written FO ( ∼ , < , + 1 ) ) over one-counter automata. We consider several classes of one-counter automata (mainly deterministic vs. nondeterministic) and several logical fragments (restriction on the number of registers or variables and on the use of propositional variables for control states). The logics have the ability to store a counter value and to test it later against the current counter value. We show that model checking LTL ↓ and FO ( ∼ , < , + 1 ) over deterministic one-counter automata is PSpace-complete with infinite and finite accepting runs. By contrast, we prove that model checking LTL ↓ in which the until operator U is restricted to the eventually F over nondeterministic one-counter automata is Σ 1 1 -complete [resp. Σ 1 0 -complete] in the infinitary [resp. finitary] case even if only one register is used and with no propositional variable. As a corollary of our proof, this also holds for FO ( ∼ , < , + 1 ) restricted to two variables (written FO 2 ( ∼ , < , + 1 ) ). This makes a difference with respect to the facts that several verification problems for one-counter automata are known to be decidable with relatively low complexity, and that finitary satisfiability problems for LTL ↓ and FO 2 ( ∼ , < , + 1 ) are decidable. Our results pave the way for model checking memoryful (linear-time) logics over other classes of operational models, such as reversal-bounded counter machines.

IEEE 802.11-Based Wireless Sensor System for Vibration Measurement

Network-based wireless sensing has become an important area of research and various new applications for remote sensing are expected to emerge. One of the promising applications is structural health monitoring of building or civil engineering structure and it often requires vibration measurement. For the vibration measurement via wireless network, time synchronization is indispensable. In this paper, we introduce a newly developed time synchronized wireless sensor network system. The system employs IEEE 802.11 standard-based TSF-counter and sends the measured data with the counter value. TSF based synchronization enables consistency on common clock among different wireless nodes. We consider the scale effect on synchronization accuracy and evaluated the effect by taking beacon collisions into account. The scalability issue by numerical simulations is also studied. This paper also introduces a newly developed wireless sensing system and the hardware and software specifications are introduced. The experiments were conducted in a reinforced concrete building to evaluate synchronization accuracy. The developed system was also applied for a vibration measurement of a 22-story steel structured high rise building. The experimental results showed that the system performed more than sufficiently.

A Distributed Fair Scheduling Scheme With a New Analysis Model in IEEE 802.11 Wireless LANs

In this paper, we study the performance of 802.11 wireless local area networks (WLANs) and propose a distributed packet scheduling scheme that improves the short-term fairness among stations in a WLAN. First, we present a completely different analytical model to analyze the performance of 802.11 distributed coordination function (DCF), which models the channel contention dynamics of an IEEE 802.11 system, rather than the individual user perspective adopted by most previous analytical works based on Markov chains. Our model is much simpler than previous Markov chain models that have been used popularly to model the DCF's binary exponential backoff (BEB) procedure. In our model, the backoff stage and the value of the backoff counter are represented as a queueing system and the residual service time at the queue, respectively. Then, we model an entire 802.11 WLAN as a closed queuing network and derive the performance of the 802.11 DCF based on the queueing theory. Next, by exploiting the analytic results, we develop a simple distributed runtime estimation scheme that effectively calculates the number of contending stations. Finally, we propose a distributed packet scheduling scheme that improves the short-term fairness to the IEEE 802.11 network. The scheme utilizes the token bucket mechanism and controls the packet arrival rate sent down to the medium access control (MAC) layer from the logical link control (LLC) layer by adjusting the token-generation rate according to the measured channel contention level. Performance evaluation results show that our scheduling scheme provides a higher degree of short-term fairness as well as throughput improvement.

Efficient dynamic bandwidth allocation for FSAN-compliant GPON

We suggest an immediate allocation with colorless grant (IACG) method for dynamic bandwidth allocation of a gigabit passive optical network (GPON) system. The suggested method is based on the GigaPON Access Network (GIANT) media access control (MAC) method. The IACG method can assign the transmission bandwidth regardless of the value of a scheduling counter, whereas the GIANT MAC method can assign the transmission bandwidth only when the scheduling counter has a value of 1. Also, unlike the GIANT MAC method, the IACG method utilizes the unallocated remainder of the transmission bandwidth. At the end of scheduling, the IACG MAC method assigns the unallocated remainder to each optical network unit (ONU) with an equal share. Using computer simulations with the self-similar traffic model, we show that the IACG method dramatically outperforms the GIANT MAC method in mean delay and frame-loss rate.

무인 헬기 자동 착륙을 위한 3차원 위치 추적 시스템

This paper describes a location tracking system to guide landing process of an Unmanned Helicopter(UMH) exploiting MIT Cricket nodes. For automatic landing of a UMH, a precise positioning system is indispensable. However, GPS(Global Positioning System) is inadequate for tracking the three dimensional position of a UMH because of large positioning errors. The Cricket systems use Time-Difference-of-Arrival(TDoA) method with ultrasonic and RF(Radio Frequency) signals to measure distances. They operate in passive mode in that a listener attached to a moving device receives distance signals from several beacons located at fixed points on ground. Inevitably, this passive type of implementation causes large disturbances in measuring distances between beacons and the listener due to wind blow from propeller and turbulence of UMH body. To cope with this problem, we proposed active type of implementation for positioning a UMH. In this implementation, a beacon is set up at UMH body and four listeners are located at ground area at least where the UMH will land. A pair of Ultrasonic and RF signals from the beacon arrives at several listeners to calculate the position of the UMH. The distance signals among listeners are synchronized with a counter value appended to each distance signals from the beacon.

Channel-Aware Distributed Throughput-Based Fair Queueing for Wired and Wireless Packet Communication Networks

Fair queueing is a service scheduling discipline to pursue the fairness among users in packet communication networks. Many fair queueing algorithms, however, have problems of computational overhead since the central scheduler has to maintain a certain performance counter for each flow of user packets based on the global virtual time. Moreover, they are not suitable for wireless networks with high probability of input channel errors due to the lack or complexity in the compensation mechanism for the recovery from the error state. In this paper, we propose a new, computationally efficient, distributed fair queueing scheme, which we call Channel-Aware Throughput Fair Queueing (CATFQ), that is applicable to both wired and wireless packet networks. In our CATFQ scheme, each flow is equipped with a counter that measures the weighted throughput achievement while it has a backlog of packets. At the end of every service to a packet, the scheduler simply selects a flow with the minimum counter value as the one from which a packet is served next. We show that the difference between any two throughput counters is bounded. Our scheme significantly reduces the scheduler's computational overhead and guarantees fair throughput for all flows. For wireless networks with error-prone channels, the service chance lost in bad channel condition is compensated quickly as the channel recovers. Our scheme suppresses the service for leading flows, brings short-term fairness for flows without channel errors, and achieves long-term fairness for all flows. These merits are verified by simulation.

Accurate branch prediction for short threads

Multi-core processors, with low communication costs and high availability of execution cores, will increase the use of execution and compilation models that use short threads to expose parallelism. Current branch predictors seek to incorporate large amounts of control flow history to maximize accuracy. However, when that history is absent the predictor fails to work as intended. Thus, modern predictors are almost useless for threads below a certain length. Using a Speculative Multithreaded (SpMT) architecture as an example of a system which generates shorter threads, this work examines techniques to improve branch prediction accuracy when a new thread begins to execute on a different core. This paper proposes a minor change to the branch predictor that gives virtually the same performance on short threads as an idealized predictor that incorporates unknowable pre-history of a spawned speculative thread. At the same time, strong performance on long threads is preserved. The proposed technique sets the global history register of the spawned thread to the initial value of the program counter. This novel and simple design reduces branch mispredicts by 29% and provides as much as a 13% IPC improvement on selected SPEC2000 benchmarks.

Accurate branch prediction for short threads

Multi-core processors, with low communication costs and high availability of execution cores, will increase the use of execution and compilation models that use short threads to expose parallelism. Current branch predictors seek to incorporate large amounts of control flow history to maximize accuracy. However, when that history is absent the predictor fails to work as intended. Thus, modern predictors are almost useless for threads below a certain length. Using a Speculative Multithreaded (SpMT) architecture as an example of a system which generates shorter threads, this work examines techniques to improve branch prediction accuracy when a new thread begins to execute on a different core. This paper proposes a minor change to the branch predictor that gives virtually the same performance on short threads as an idealized predictor that incorporates unknowable pre-history of a spawned speculative thread. At the same time, strong performance on long threads is preserved. The proposed technique sets the global history register of the spawned thread to the initial value of the program counter. This novel and simple design reduces branch mispredicts by 29% and provides as much as a 13% IPC improvement on selected SPEC2000 benchmarks.

Accurate branch prediction for short threads

Multi-core processors, with low communication costs and high availability of execution cores, will increase the use of execution and compilation models that use short threads to expose parallelism. Current branch predictors seek to incorporate large amounts of control flow history to maximize accuracy. However, when that history is absent the predictor fails to work as intended. Thus, modern predictors are almost useless for threads below a certain length. Using a Speculative Multithreaded (SpMT) architecture as an example of a system which generates shorter threads, this work examines techniques to improve branch prediction accuracy when a new thread begins to execute on a different core. This paper proposes a minor change to the branch predictor that gives virtually the same performance on short threads as an idealized predictor that incorporates unknowable pre-history of a spawned speculative thread. At the same time, strong performance on long threads is preserved. The proposed technique sets the global history register of the spawned thread to the initial value of the program counter. This novel and simple design reduces branch mispredicts by 29% and provides as much as a 13% IPC improvement on selected SPEC2000 benchmarks.

Development of Time Synchronized Wireless Sensor Network

Network based wireless sensing has become an important area of research and various new applications for remote sensing are expected to emerge. One of the promising applications is structural health monitoring of building or civil engineering structure and it often requires vibration measurement. For the vibration measurement via wireless network, time synchronization is indispensable. In this paper, we introduce a newly developed time synchronized wireless sensor network system. The system employs IEEE 802.11 standard based TSF counter and sends the measured data with the counter value. It enables consistency on common clock among different wireless nodes. We describe the accuracy evaluation by simulation studies when the size of nodes increased. The hardware and software specifications of the developed wireless sensing system are shown. The experiments were conducted in a three-street reinforced concrete building and results showed the system performs more than sufficiently.

Risk Assessment for One-Counter Threads

Threads as contained in a thread algebra are used for the modeling of sequential program behavior. A thread that may use a counter to control its execution is called a ‘one-counter thread’. In this paper the decidability of risk assessment (a certain form of action forecasting) for one-counter threads is proved. This relates to Cohen’s impossibility result on virus detection (Comput. Secur. 6(1), 22–35, 1984). Our decidability result follows from a general property of the traces of one-counter threads: if a state is reachable from some initial state, then it is also reachable along a path in which all counter values stay below a fixed bound that depends only on the initial and final counter value. A further consequence is that the reachability of a state is decidable. These properties are based on a result for ω-one counter machines by Rosier and Yen (SIAM J. Comput. 16(5), 779–807, 1987).

中間処理プロセス・業界の現状と課題 電線リサイクルの現状と課題

Now, by recycling processing of used electric cables, the recycling rate of copper and aluminum of the conductor are almost 100%, but the plastic separated from the conductor is about 50%. Those plastics are dealt with for counter value. The remaining plastics are discarded as industrial waste. As a technical subject the separation of the nugget plastics is important.Recently the increase in export of used electric cables is remarkable; especially the export to China is increasing. In China, plastic is thoroughly separated at cheap personnel expenses and the plastic can be sold for counter value. It is because the Chinese purchase price is higher than Japanese. For that reason, the amount of processing used electric cable in Japanese manufacture is decreasing and it is doubtful of continuation. Copper and plastics which are the material of electric cables are recyclable materials. They are worried about exhaustion in near future. Used electric cables should be changed into various material, and it should be re-made to recycle as a material of electric cables. Japan Electric Cable Technology Center investigated the present condition and the problem of waste electric cable recycling, at the same time it studied various kinds of recycling technology. The present condition of Japanese electric cable recycling is reported.

A high-resolution time-to-digital converter implemented in field-programmable-gate-arrays

A high-resolution time-to-digital converter (TDC) implemented in a general purpose field-programmable-gate-array (FPGA) is presented. Dedicated carry lines of an FPGA are used as delay cells to perform time interpolation within the system clock period and to realize the fine time measurement. Two Gray-code counters, working on in-phase and out-of-phase system clocks respectively, are designed to get the stable value of the coarse time measurement. The fine time code and the coarse time counter value, along with the channel identifier, are then written into a first-in first-out (FIFO) buffer. Tests have been done to verify the performance of the TDC. The resolution after calibration can reach 50 ps

Synchro controller of radar on FPGA

This paper mainly represents the realization of synchro controller based on the programmable logic devices FPGA by request of HF ground wave radar synchro controller under the instance of making the best of the virtues of FPGA. This design introduces the data communication between PC and synchro controller byI2C Bus, which can carry the synchronous signals’ parameters to RAM of synchro controller, then according to the theory that the result of comparing counter value with signals’ parameters is the needed wave, we produce all waves HF ground wave radar needs, moreover all waves are produced time-sharing in order to save resources.