A Detailed Analysis of Contemporary ARM and x86 Architectures

RISC vs. CISC wars raged in the 1980s when chip area and processor design complexity were the primary constraints and desktops and servers exclusively dominated the computing landscape. Today, energy and power are the primary design constraints and the computing landscape is significantly different: growth in tablets and smartphones running ARM (a RISC ISA) is surpassing that of desktops and laptops running x86 (a CISC ISA). Further, the traditionally low-power ARM ISA is entering the high-performance server market, while the traditionally high-performance x86 ISA is entering the mobile low-power device market. Thus, the question of whether ISA plays an intrinsic role in performance or energy efficiency is becoming important, and we seek to answer this question through a detailed measurement based study on real hardware running real applications. We analyze measurements on the ARM Cortex-A8 and Cortex-A9 and Intel Atom and Sandybridge i7 microprocessors over workloads spanning mobile, desktop, and server computing. Our methodical investigation demonstrates the role of ISA in modern microprocessors? performance and energy efficiency. We find that ARM and x86 processors are simply engineering design points optimized for different levels of performance, and there is nothing fundamentally more energy efficient in one ISA class or the other. The ISA being RISC or CISC seems irrelevant

Could Intelligent Speed Adaptation make overtaking unsafe?

This driving simulator study investigated how mandatory and voluntary ISA might affect a driver's overtaking decisions on rural roads, by presenting drivers with a variety of overtaking scenarios designed to evaluate both the frequency and safety of the manoeuvres. In half the overtaking scenarios, ISA was active and in the remainder ISA was switched off. A rural road was modelled with a number of 2 + 1 road sections, thus allowing drivers a protected overtaking opportunity. The results indicate that drivers became less inclined to initiate an overtaking manoeuvre when the mandatory ISA was active and this was particularly so when the overtaking opportunity was short. In addition to this, when ISA was activated drivers were more likely to have to abandon an overtaking, presumably due to running out of road. They also spent more time in the critical hatched area - a potentially unsafe behaviour. The quality of the overtaking manoeuvre was also affected when mandatory ISA was active, with drivers pulling out and cutting back in more sharply. In contrast, when driving with a voluntary ISA, overtaking behaviour remained mostly unchanged: drivers disengaged the function in approximately 70% of overtaking scenarios. The results of this study suggest that mandatory ISA could affect the safety of overtaking manoeuvres unless coupled with an adaptation period or other driver support functions that support safe overtaking

What drives the Acceptability of Intelligent Speed Assistance (ISA)? Modeling acceptability of ISA

6370 individuals responded in Belgium (Flanders region) and 1158 persons in The Netherlands on a web-survey about ISA. A model has been estimated, by using SEM, to find out which predefined indicators would be relevant to define the acceptability of ISA. Background factors, contextual issues, and ISA-device related factors were used as indicators to predict the level of acceptability. The factors that were used in the model were based on the methods used in past ISA trials, acceptance and accep-tability theories and models. The effectiveness of ISA (1), equity (2), effectiveness of ITS (3) and personal and social aims (4), were the four variables that had the largest total effect on the acceptability of ISA. Effectiveness was found a relevant predictor for acceptance in many trials (Morsink et al, 2006). The model showed that the willingness of drivers to adopt ISA increases if they experience the system in practice: if people are convinced that ISA will assist to maintain the legal speed in different speed zones, the acceptance will be higher (Van der Pas et al., 2008). Hence, trials seem a good way to demonstrate the effectiveness of ISA. However, trials typically do not allow many people to try out ISA. Therefore, communi-cation strategies that focus on the ISA-effectiveness would be helpful to convince people about the benefits of using such a system. Often when new driver support technologies are intro-duced – especially when it could restrict certain freedom in driving – a majority of the population is reluctant when it comes to ‘buy or use’ the system. In some studies (see Morsink et al., 2006; Marchau et al., 2010) the willingness to pay was reported to be a good predictor for acceptability. However, in the present study the effect of willing-ness to pay was very low or even absent; hence it may be as-sumed that better indicators are put in the model than the willing-ness to pay. With respect to context indicators, ‘personal and social aims’ seemed to be the variable with the highest influence on accep-tability. Drivers, who rate social aims above personal aims with respect to speed and speeding, will accept ISA more. Personal and social aims had also a high influence on most of the device spe-cific indicators. Furthermore, drivers who speed for their personal benefit were found to rather speed more often. Drivers who speed in high-speed zones would also be less inclined to accept ISA. This is in line with previous findings (e.g. Jamson et al., 2006), frequent speeders would support ISA less; those drivers who would benefit most of ISA would be less likely to use it. This is an important finding when considering the strategies for implementing ISA. Some studies (e.g. Morsink et al., 2006) indicated that to increase the acceptability, implementation strategies and campaigns could focus on other benefits of ISA (like reducing speeding tickets, emissions etc.). According to our study these secondary effects have rather small effects to increase acceptability. Drivers who like to speed would even care less for these secondary benefits of ISA. The youngest group of drivers (<25 years old) would influence responsibility awareness negatively. These younger drivers are also less convinced that certain behaviour or circumstances could cause accidents. Many studies indicated that young drivers over-estimate their own driving skills, drive faster and are less aware of accident causes (Shinar et al., 2001). For the implementation of ISA – although there is no direct relationship between younger age and acceptability – a different strategy is needed to convince this group of drivers. Awareness campaigns and communication should be deployed during their education, however, road safety education and training stops during secondary school or higher education (OECD, 2006). Drivers between 25 and 45 years old would also be less inclined to accept ISA, mainly considered out of indirect effects in the esti-mated model. This group of drivers may be labelled as one of the most active groups of drivers. Another aspect is that both of the "significant found age groups were influenced by social norms. This may be very important in implementation strate-gies. For instance, role models could be used in ISA driving. This strategy was also used in the Belgian trial to gain more publicity and attention. The positive image and the improved information communication of ISA as a possible measure in road-safety have led to several voted resolutions in the Belgian federal parliament and senate (Vlassenroot et al. 2007)

Network effects of intelligent speed adaptation systems

Intelligent Speed Adaptation (ISA) systems use in-vehicle electronic devices to enable the speed of vehicles to be regulated externally. They are increasingly appreciated as a flexible method for speed management and control, particularly in urban areas. On-road trials using a small numbers of ISA equipped vehicles have been carried out in Sweden, the Netherlands, Spain and the UK. This paper describes the developments made to enhance a traffic microsimulation model in order to represent ISA implemented across a network and their impact on the networks. The simulation modelling of the control system is carried out on a real-world urban network, and the impacts on traffic congestion, speed distribution and the environment assessed. The results show that ISA systems are more effective in less congested traffic conditions. Momentary high speeds in traffic are effectively suppressed, resulting in a reduction in speed variation which is likely to have a positive impact on safety. Whilst ISA reduces excessive traffic speeds in the network, it does not affect average journey times. In particular, the total vehicle-hours travelling at speeds below 10 km/hr have not changed, indicating that the speed control had not induced more slow-moving queues to the network. A significant, eight percent, reduction in fuel consumption was found with full ISA penetration. These results are in accordance with those from field trials and they provide the basis for cost-benefit analyses on introducing ISA into the vehicle fleet. Contrary to earlier findings from the Swedish ISA road trials, these network simulations showed that ISA had no significant effect on emission of gaseous pollutants CO, NOx and HC. Further research is planned to investigate the impact on emission with a more comprehensive and up to date modal emission factor database

Would those who need ISA, use it? Investigating the relationship between drivers' speed choice and their use of a voluntary ISA system

Intelligent Speed Adaptation (ISA) is one of the most promising new technologies for reducing the prevalence and severity of speed-related accidents. Such a system could be implemented in a number of ways, representing various "levels of control" over the driver. An ISA system could be purely advisory or could actually control the maximum speed of a vehicle. A compromise would be to introduce a system that allows a driver to choose when to engage ISA, thus creating a “voluntary” system. Whilst these voluntary systems are considered more acceptable by drivers, they will not offer safety benefits if they are not used by the driver. Two studies were carried out that examined the relationship between drivers’ reported and actual speeding behaviour, their propensity to engage a voluntary ISA system and their attitudes towards such a system. These studies were carried out in a driving simulator and in an instrumented vehicle. In both the studies, drivers’ propensity to exceed the speed limit was lowered when ISA was available but this effect was confined to the lower speed limits. In general, drivers engaged ISA for approximately half of their driving time, depending on the speed limit of the road and indeed, on the nature of the road and the surrounding traffic. This was particularly true in the field study where drivers were more inclined to “keep up with” the surrounding traffic. The results from the on-road study indicated that those drivers who considered ISA to be both a useful and pleasant system, were overall more likely to engage it. However, those drivers who confessed to enjoying exceeding the speed limit were less likely to use ISA. This is an important finding when considering the mechanisms for implementing ISA: those drivers who would benefit most would be less likely to use a voluntary system

A descriptive review and classification of organizational information security awareness research

Information security awareness (ISA) is a vital component of information security in organizations. The purpose of this research is to descriptively review and classify the current body of knowledge on ISA. A sample of 59 peer-reviewed academic journal articles, which were published over the last decade from 2008 to 2018, were analyzed. Articles were classified using coding techniques from the grounded theory literature-review method. The results show that ISA research is evolving with behavioral research studies still being explored. Quantitative empirical research is the dominant methodology and the top three theories used are general deterrence theory, theory of planned behavior, and protection motivation theory. Future research could focus on qualitative approaches to provide greater depth of ISA understanding

TriCheck: Memory Model Verification at the Trisection of Software, Hardware, and ISA

Memory consistency models (MCMs) which govern inter-module interactions in a shared memory system, are a significant, yet often under-appreciated, aspect of system design. MCMs are defined at the various layers of the hardware-software stack, requiring thoroughly verified specifications, compilers, and implementations at the interfaces between layers. Current verification techniques evaluate segments of the system stack in isolation, such as proving compiler mappings from a high-level language (HLL) to an ISA or proving validity of a microarchitectural implementation of an ISA. This paper makes a case for full-stack MCM verification and provides a toolflow, TriCheck, capable of verifying that the HLL, compiler, ISA, and implementation collectively uphold MCM requirements. The work showcases TriCheck's ability to evaluate a proposed ISA MCM in order to ensure that each layer and each mapping is correct and complete. Specifically, we apply TriCheck to the open source RISC-V ISA, seeking to verify accurate, efficient, and legal compilations from C11. We uncover under-specifications and potential inefficiencies in the current RISC-V ISA documentation and identify possible solutions for each. As an example, we find that a RISC-V-compliant microarchitecture allows 144 outcomes forbidden by C11 to be observed out of 1,701 litmus tests examined. Overall, this paper demonstrates the necessity of full-stack verification for detecting MCM-related bugs in the hardware-software stack.Comment: Proceedings of the Twenty-Second International Conference on Architectural Support for Programming Languages and Operating System