Stop Position Research Articles

A surrogate safety assessment of scrambled phase intersections

Traffic safety remains a top priority for policymakers and researchers, prompting numerous investigations to enhance safety for all road users, particularly pedestrians. This paper evaluates the safety impact of implementing scramble phases at intersections with a high concentration of vulnerable road users in Edmonton, Canada. The study spans three periods: prior to the scramble phase installation, immediately post-installation, and 6 months post-installation. The evaluation employs two key methodologies. Firstly, it observes the frequency of right-turn-on-red violations to assess driver behaviour. Secondly, the study investigates the frequency of serious conflicts, utilizing safety indicators such as time to collision, time difference to point of intersection, and distance between stop position and pedestrian. The findings suggest that introducing scramble phases positively impacts intersection safety, notably reducing severe conflicts and total right-turn-on-red violations. These results offer valuable insights for policymakers and researchers working towards safer urban traffic environments.

Highly Sensitive Detection of Genomic DNA Using Rapid Real-Time PCR Based on Oscillating Flow

Some individuals are diagnosed with urethritis owing to the detection of gonorrhoea or chlamydia infection through clinical tests; however, there are cases in which neither is detected despite exhibiting symptoms. One of the causative bacteria of non-chlamydial non-gonococcal urethritis is Mycoplasma genitalium, and real-time polymerase chain reaction (qPCR), an accurate examination of causative bacteria for proper drug administration, has been used for its detection. However, given that qPCR is time-consuming, applying it to same-day testing is difficult. Therefore, a rapid qPCR system was developed using a microfluidic device.The microfluidic device used for rapid thermal cycling with oscillating flow in each detection unit was 76 mm × 52 mm × 4 mm in size. The PCR solution was injected into the microchannel from the inlet. The microfluidic device, including the liquid plug, was placed on the chip holder, and three small heaters were embedded into the rapid qPCR system. The temperature of each heater was constantly controlled for reverse transcription (optionally), DNA denaturation and ex-tension by DNA polymerase for PCR. Furthermore, both ends of the microchannel were automatically connected with pneumatic lines using the needles installed in the upper cover of the chip holder when pushed down. This system employed a pair of microblowers as the driving force for the reciprocating liquid transfer. When the microblower was turned off, it quickly released the pressure between the liquid plug and microblower without additional valves, such that the liquid transfer in the microchannel could be stopped at any position immediately. The liquid plug of the PCR solution was reciprocally transferred at programmed timing by switching the two microblowers controlled by the main unit. The detection unit also had an array of three fluorescence detectors aligned along the microchannel. To detect the passage of the PCR solution, the fluorescence of fluorescein mixed with the PCR solution was measured in the middle of the two heaters for denaturation and extension. The fluorescence signal was used to precisely control the stop position on the heater. The remaining two fluorescence detectors were located above the two heaters individually and were used for liquid position detection and evaluation of the amplification of the MgPa gene and internal control.A standard curve was evaluated against gDNA standards of M. genitalium. For the thermal cycle conditions, heating at 96˚C for 10 s, 3 s at 96˚C, and 6 s at 59˚C was repeated 50 times. A dilution series of 0.063 to 5.0×104 copies/run was used as the gDNA concentration of M. genitalium. In addition, to confirm the detection frequency at low concentrations, samples were tested nine times at concentrations where the presence or absence of gDNA in the PCR solution varied statistically. Fig. (a) shows the detection frequency at each concentration of gDNA of M. genitalium. The rapid RT-PCR system was amplified from extremely low concentrations of samples even if the number was < 1 copy/run, although the frequency was not 100%. Fig. (b) shows the standard curve obtained from these amplification curves, which shows good linearity up to 5 copies/run. The PCR efficiency was calculated to be 96.3%. For concentrations of < 5 copies, the success or failure of detection was speculated to depend on the stochastic inclusion of the template DNA in the PCR solution. Fig. (c) shows the detection frequency for each gDNA concentration of M. genitalium and a fitting curve based on the cumulative distribution function (CDF) of the Poisson distribution. The expected value of the maximum likelihood CDF corresponded to 1 copy/run, which would theoretically yield the best LOD. The LOD with a 95% confidence interval (CI) was estimated to be 3 copies/run from this fitting curve. The statistically estimated limit of detection was equivalent to the amplification from a single molecule of genomic DNA, and the PCR efficiency was calculated to be almost 100%. Moreover, the analysis time for a negative judgement obtained without amplification was within 11 min. Thus, the developed rapid RT-PCR system would be useful for the same-day testing of infectious bacteria. Figure 1

Research and Prediction of Wear Characteristics of Alfalfa Densification Die Based on the Discrete Element Method

In this study, the wear characteristics of the die were tested and analyzed through compaction tests, and the distribution of wear depth along the direction toward the extrusion outlet was obtained. A discrete element method (DEM) model of the die’s wear process was established. The results show that the severe wear area is located near the stop position of the compression rod, forming a plow-shaped wear area along the extrusion direction, accompanied by fatigue peeling. The wear depth gradually decreases towards the extrusion outlet. The DEM model partially reveals the occurrence of the wear phenomenon, but the particle motion speed deviates from the actual situation. The maximum compression force value range during the DEM compression stage is within the actual maximum compression force value range, and the relative error range of the average maximum compression force is less than 2%. By verifying the formula to calibrate the model, the calibrated model is compared with the actual mold wear, and the predicted value is close to the actual test result. The DEM can be used to explore the wear mechanism and predict the die’s wear failure process, laying the foundation for optimizing die wear resistance design.

Dynamic Modeling and Simulation of a Discrete Incremental Hydraulic Positioning System Controlled by Binary Valves

This article presents the conceptual design, operation principle, dynamic modeling, and simulation results of a discrete incremental hydraulic positioning system (DIHPS) intended for use in high-precision, heavy-load industrial automation solutions. An original solution for precise incremental step positioning using DIHPS is proposed, comprising an n-step linear double-acting hydraulic actuator (HA) with a double rod, cylinder sleeve with outflow gaps, binary valves (BVs) bleed-off into the tank, and fixed throttle valves (TRVs) at the inlets of the actuator chambers. The discrete incremental shift of the HA is determined by controlling the opening and closing of the individual BVs, and the step shift of the HA piston stops at the opening location of the BV. A dynamic model of incremental step shift for DIHPS is developed, considering the behavior and relationships of its individual elements. A dynamic model of HA with and without a hydropneumatic accumulator (HPA) is presented. HPA has been shown to effectively dampen piston vibrations and pressure peaks at the HA stop position. The design assumptions, dynamic models, and discrete incremental positioning of the DIHPS are verified by simulation tests and assessed with quantitative indicators. Innovative DIHPSs have significant practical potential in the discrete incremental positioning of heavy loads.

Evaluating Bus Transit System for Efficient Last Mile Transportation in Universiti Teknologi MARA (UiTM) Shah Alam

As the leading example in sustainable transportation, universities should have an optimal and precedent system. Universiti Teknologi MARA (UiTM) campus provides bus transportation for students. However, with the vast coverage of the campus area, the bus stops should be distributed evenly. This research aims to evaluate the bus stop position to find the optimal last mile distance concerning the principle of Universal Design, precisely the aspect of low physical effort. This research uses the method of space syntax to analyse the spatial arrangement of urban environments, including transportation systems. It is based on the idea that the spatial structure of an environment affects its usability and accessibility and that the arrangement of elements can be optimised to improve accessibility and reduce physical effort. As a result, this research finds that UiTM's current bus stop distribution needs to be improved. It should have filled the demand for several spots, such as dormitories, sports centers, and faculties. Adding bus stops or bus volume is the appropriate solution to this finding, considering the growth of student numbers and the upcoming LRT station development. This research has proven a new depth perspective by combining topologic, angular, and metriclogic. The findings of this research are beneficial in planning bus stops that carefully consider the universal design for all users wherever they live and work.

Sliding Mode Wheel Slip Control for Regenerative Braking of an All-Wheel-Drive Electric Vehicle

Abstract Regenerative braking is one of the main advantages of electric propulsion systems. In such systems, the vehicle brake controller has to prioritize safety while maximizing the recovered energy at all times. This paper proposes a two-step hierarchical brake controller for a dual-motor all-wheel-drive electric vehicle. In the first step, a novel sliding mode controller (SMC) generates the total braking torque on each axle to independently control the slip on the front and rear wheels. In the second step, the torque split controller assigns motor and friction brake torques to maximize the recovered energy. By incorporating the effects of changing vehicle speed, the proposed SMC controller accounts for the nonlinearities in vehicle dynamics and tire model and considers the weight transfer due to vehicle deceleration while being robust to disturbances. Using simulations, we show that while the traditional SMC formulation is not effective during emergency braking scenarios, the proposed formulation successfully generates control commands to bring the vehicle to a stop position at a minimum distance. Furthermore, our controller can maintain both wheels in the stable slip region, even when starting from a locked position. The performance of the proposed controller is evaluated for an emergency braking scenario and on an aggressive segment of the US06 cycle.

Led-Seq:ligation-enhanced double-end sequence-based structure analysis of RNA.

Structural analysis of RNA is an important and versatile tool to investigate the function of this type of molecules in the cell as well as in vitro. Several robust and reliable procedures are available, relying on chemical modification inducing RT stops or nucleotide misincorporations during reverse transcription. Others are based on cleavage reactions and RT stop signals. However, these methods address only one side of the RT stop or misincorporation position. Here, we describe Led-Seq, a new approach based on lead-induced cleavage of unpaired RNA positions, where both resulting cleavage products are investigated. The RNA fragments carrying 2', 3'-cyclic phosphate or 5'-OH ends are selectively ligated to oligonucleotide adapters by specific RNA ligases. In a deep sequencing analysis, the cleavage sites are identified as ligation positions, avoiding possible false positive signals based on premature RT stops. With a benchmark set of transcripts in Escherichia coli, we show that Led-Seq is an improved and reliable approach based on metal ion-induced phosphodiester hydrolysis to investigate RNA structures in vivo.

Effect of starting position of crankshaft on transient body vibrations of reciprocating compressor

The maximum reciprocating compressor vibrations occur during the startup and shutdown operations and understanding the factors that influence the transient vibrations can help in developing solutions to reduce the excessive displacements. In this study, the effect of crankshaft starting position on the vibration phenomenon is investigated and the optimal starting position to deliver a smooth start is proposed. The structural forces are analytically modeled to estimate the body displacements by considering the system resonance frequencies and modal vectors. An experimental setup is also constructed to validate the prediction model results, with the integration of an encoder to track the crankshaft angular position and transducers to measure the discharge and suction pressures. The transient responses of three different crankshaft start positions are then compared using the experimental setup and the analytical model. The results indicate that if the crankshaft starts to rotate from positions close to the bottom dead center, a higher amount of startup vibrations is observed, revealing the optimal starting position zone.The magnetization effect can potentially be addressed by the sensorless starting strategy developed by Lee et al. (2008) that implements a phase current controller for a smoother startup. While out of scope for this study, shutdown strategies can also be devised to have the piston consistently land at the favorable SAP range. By separately investigating the instances when the ‘stop’ command is provided to the steady-state operating compressor, solutions that attempt to replicate the conditions that lead to the favorable stop position can be developed; a limiting factor in mass production will be implementing the encoder for continuous position tracking and an accompanying undesirable cost increase in manufacturing. Nevertheless, the investigation of passive and active strategies is ripe for research in literature.

Design and Experiments of Autonomous Path Tracking Based on Dead Reckoning

Path tracking is an important component of autonomous driving and most current path tracking research is based on different positioning sensors, such as GPS, cameras, and LIDAR. However, in certain extreme cases (e.g., in tunnels or indoor parking lots), if these sensors are unavailable, achieving accurate path tracking remains a problem that is worthy of study. This paper addresses this problem by designing a dead reckoning method that is solely reliant on wheel speed for localization. Specifically, a differential drive model is first used for estimating the current relative vehicle position in real time by rear wheel speed, and the deviation between the current path and the reference path is then calculated using the pure pursuit algorithm as a means of obtaining the target steering wheel angle and vehicle speed. The steering wheel and vehicle speed signals are then output by two PID controllers in order to control the vehicle, and the automatic driving path tracking is ultimately realized. Through exhaustive tests and experiments, the stop position error and tracking process error are compared under different conditions, and the effects of vehicle speed, look-ahead distance, starting position angle, and driving mode on tracking accuracy are analyzed. The experimental results show the average error of the end position to be 0.26 m, 0.383 m, and 0.505 m when using BMW-i3 to drive one lap automatically at speeds of 5 km/h, 10 km/h, and 15 km/h in a test area with a perimeter of approximately 200 m.

Rainbow trapping and releasing based on the topological photonic crystals and a gradient 1D array

Topological photonic crystal provides a platform for robust energy transport in photonic systems. In this letter, we propose a method for realizing rainbow trapping and releasing based on the topologically protected defect modes in dielectric photonic crystals. The photonic states of different frequencies are separated and trapped at different positions to form the topological rainbow. The all-dielectric planar nanostructures consist of deformed honeycomb lattices and a gradient 1D array, which is distinct from previous platforms where edge states appear at the interface between trivial and nontrivial crystals. Due to the simplification of the configuration, we can selectively control the stop position of the wave by modifying the bottom row of dielectric rods so that light can switch between the trapping state and releasing state. The robustness of the slowing light system is also investigated. These results are beneficial to multiple frequency tuning. The simplified structure could offer a novel method for micro-miniaturizing and applying optical communication equipment, such as optical storage and optical buffer.

Thoracolumbar And Lumbopelvic Spinal Alignment During The Deadlift Exercise: A Comparison Between Men And Women.

BackgroundA neutral spinal alignment is considered important during the execution of the deadlift exercise to decrease the risk of injury. Since male and female powerlifters experience pain in different parts of their backs, it is important to examine whether men and women differ in spinal alignment during the deadlift.ObjectivesThe purpose of this study was to quantify the spinal alignment in the upper (thoracolumbar, T11-L2) and lower (lumbopelvic, L2-S2) lumbar spine during the deadlift exercise in male and female lifters. Secondary aims were to compare lumbar spine alignment during the deadlift to standing habitual posture, and determine whether male and female lifters differ in these aspects.Study DesignObservational, Cross-sectional.MethodsTwenty-four (14 men, 10 women) lifters performed three repetitions of the deadlift exercise using 70% of their respective one-repetition maximum. Spinal alignment and spinal range of motion were measured using three inertial measurement units placed on the thoracic, lumbar and sacral spine. Data from three different positions were analyzed; habitual posture in standing, and start and stop positions of the deadlift, i.e. bottom and finish position respectively.ResultsDuring the deadlift, spinal adjustments were evident in all three planes of movement. From standing habitual posture to the start position the lumbar lordosis decreased 13° in the upper and 20° in the lower lumbar spine. From start position to stop position the total range of motion in the sagittal plane was 11° in the upper and 22° in the lower lumbar spine. The decreased lumbar lordosis from standing habitual posture to the start position was significantly greater among men.ConclusionsMen and women adjust their spinal alignment in all three planes of movement when performing a deadlift and men seem to make greater adjustments from their standing habitual posture to start position in the sagittal plane.Level of Evidence3

Assessing and mitigating the distortion and stress during electron beam welding of a large shell-flange structure

Electron beam (EB) welding can efficiently join large-scale components using one single autogenous pass, but it still faces challenges associated with weld-induced distortion and stress. This study investigates EB welding in a low-alloy steel thick-section shell-flange structure for a small modular reactor. A 3D thermal-metallurgical-mechanical model is developed to assess the weld-induced distortion and stress, as well as the strategy to mitigate them. When no restraint is imposed on the circumferential weld plane, an opening and sliding gap develops during the EB welding, which can cause weld defects and even process failure. Restraint through tack welds can effectively mitigate the gapping distortion, but it generates high transient tensile stress in the tack weld. Circumferentially continuous tack weld is preferential over circumferentially discrete tack welds to minimise the tensile stress. The final residual stress is insensitive to the tack-weld restraint, and the stress distribution in the steady-state welding region is broadly similar to that found in plate butt welds. However, concentration of residual stresses with high triaxiality occurs in the weld stop region, with high tensile stresses generated just behind the beam stop location, which cannot be diminished by overlap welding or change of weld stop position. The mechanisms responsible for the distortion and the transient and residual stresses are analysed. This study could provide rational basis for designing weld restraint to control distortion and guiding stress mitigation strategy for crack-susceptible region in EB weldments.

Fast scanning in x-ray microscopy: the effects of offset in the central stop position.

Scanning of lightweight circular diffractive optics, separate from central stops and apertures, is emerging as an approach to exploit advances in synchrotron x-ray sources. We consider the effects in a scanning microscope of offsets between the optic and its central stop and find that scan ranges of up to about half the diameter of the optic are possible with only about a 10% increase in the focal spot width. For large scanning ranges, we present criteria for the working distance between the last aperture and the specimen to be imaged.

Design of binocular stereo vision optical system based on a single lens and a single sensor.

To reduce the number of detectors used in conventional binocular stereo cameras, while improving the measurement accuracy and compactness of the system, this paper proposes a design method for a binocular stereo vision optical system based on a single lens and a single sensor. First, based on the design principle of the traditional binocular optical system, to the best of our knowledge, a novel method of designing a framing lens array at the optical stop of the optical system is proposed to image two images on one detector simultaneously. Second, we propose a dual-frame lens array design method at the aperture stop position of the optical system that can image two images on one detector simultaneously. Then, the design principle of the method is analyzed theoretically, as well as a detailed analysis of the imaging position layout and the stray light elimination method of the dual-channel optical system. Finally, a single-lens binocular optical system with a focal length of 20 mm and a full field of view of 30° is designed using the method in this paper, and the analysis results demonstrate that the system has the advantages of good imaging quality and compact construction and provides a design idea for the design of a binocular stereo vision optical system.

Examining the efficacy of improved traffic signs and markings at flashing-light-controlled grade crossings based on driving simulation and eye tracking systems

The majority of the collisions at grade crossings occurred at flashing-light-controlled grade crossings. Understanding drivers’ behaviors and visual performances in the process of approaching the crossings is the foundation of improving crossing safety. This study aims at utilizing driving simulation and eye tracking systems to investigate the efficacy of improved traffic signs and pavement markings (PSM) at flashing-light-controlled grade crossings. The improved signs and markings were modeled in a driving simulation system and tested with a series of flashing light trigger time (FLTT) ranging from 2 s to 6 s with 1 s interval increment. Foggy conditions and drivers’ genders and vocations were considered in experiment design. Thirty-six fully-licensed drivers between 30 and 48 years participated in the experiment. Several eye-movement and behavioral measures were adopted as reflections of the subjects’ performances, including the first fixation time on signs and signals and distance to stop line, total fixation duration, compliance rate, stop position, average speed at the stop line, maximum deceleration rate and brake response time. Results showed that compared with traditional grade crossings signs and pavement markings, drivers could perceive signs timelier and fixate on the flashing-light signal earlier in PSM, especially in the scenarios of earlier FLTTs. The improvement in fixation performance and sign design contributed to a higher stop compliance rate. Importantly, it was found that drivers would hesitate to decide whether to stop or cross facing with flashing red lights, which is similar to the dilemma zone of roadway intersections. Drivers were more likely to fall into the dilemma zones when FLTT was <4 s. When FLTT was 2 s, it was particularly difficult to stop in front of the stop line. Moreover, under a foggy condition, drivers had a difficulty in searching signs and had a longer brake response time compared with a clear condition. For the characteristics of drivers, male drivers had longer fixation duration on signs than females. Professional drivers had a higher maximum deceleration rate compared with non-professional drivers. Above findings implied that improved traffic signs and markings would have a potential to improve traffic safety and deserve a field implementation in the future.

Analysis of muscle mobilization patterns and stop position of stones during sweeping each section of curling hog to hog

Purpose This is to provide essential data for training necessary for sweeping through the analysis of muscle activity generated at this time and how much sweeping and what trajectory moves the stone when the movement of the stone is controlled through sweeping. Methods To check and record the distance between the stones by checking the stop position of the stone made by sweeping each section, the length (progress distance) and width (progress direction) were recorded using a reference table and a record preparation table. With the EMG attached, a total of 60 sweeps were made 20 times each from the beginning of the section to the end of the section. Sweeping subjects were asked to sweep as much as possible under the same conditions in all three sections. Results As a result of the study, the muscle mobilization patterns of the 1st and 2nd sections of the stone with the faster speed and the 3rd section with the stone's slower speed appeared differently. It was confirmed that the sweeping motion of curling is a motion that is used evenly among the muscles of the upper extremity, and it can be verified that it is a suitable item for the development of upper body muscles. Also, the right deltoid's muscle activity rate during push and the right triceps brachii during pull was high. Conclusion Each section of the stone's sweeping effect is an exercise that has many variables, such as changes in atmospheric temperature and humidity, changes in ice temperature, temperature-size-number of pebbles, and the edge state-resilience of stones, etc. It is judged that experience can cope with these variables and requires training.

PERANCANGAN SISTEM PENGUNCIAN RODA SATU ARAH UNTUK MENGEMUDIKAN KENDARAAN RODA EMPAT DI JALAN MENANJAK

Handbrake of a vehicle is the most important thing in a safety system in maintaining theposition of the vehicle in its stop position. The hand brakes function to brake or lock the rearwheels mechanically through the connecting rods and cables. The hand brake is also to parkthe vehicle on a down/climb road. In order to facilitate the ability of four-wheeled vehicles whenstopping on the ramp due to traffic jams, a special wheel locking system is used on the ramp. Ina one-way wheel shooting system when a four-wheeled vehicle stops on the ramp, the systemlocks the wheel when the wheel rotates slightly backwards without having to pull the handbrakelever. Therefore, this research aims to describe how the work of the one-way wheel lockingsystem when on the ramp of a four-wheeled vehicle. At the design of this system researchersmake prototype as a simulation system that is approaching similar to the shape of componentsof a four-wheeled vehicle. Researchers perform test system work when the prototype movesforward and backwards to find out if the system is capable of locking the wheels when the moveis backward and release the locking wheel when moving forward without using the hand brake.Using a one-way wheel locking system is expected to facilitate the driver in driving four-wheeledvehicles on the ramp without having to use the hand brake.

Experimental study on unidirectional pedestrian flows in a corridor with a fixed obstacle and a temporary obstacle

Pedestrians may encounter obstacles during walking, and necessary actions such as reducing velocity and changing the walking direction will be made to avoid collisions. Previous studies on the effect of obstacles on pedestrian dynamics mainly focused on fixed obstacles, but the influence of temporary obstacles, such as the sudden stop caused by a moving pedestrian, has not been investigated. In this paper, a series of controlled experiments were conducted to explore the influence of fixed obstacles and temporary obstacles on the unidirectional pedestrian flow in a corridor. For the fixed obstacle, it was found that pedestrians would change their walking direction and reducing velocity at varied distances away from the obstacle. Interestingly, right side preference during evading maneuvers can be observed, and some pedestrians are not urgent to return to the initial route after passing by the obstacle. In terms of temporary obstacles, such as the sudden stop during pedestrian movement, influences of stop duration, stop position, crowd density on pedestrian movements and evading behaviors of the affected pedestrians at different positions were studied. Generally, the longer the stop duration, the more pedestrians would be affected, and the affected pedestrians may change their routes at a further distance from the temporary obstacle. By analyzing the stop position, a temporary stop near the boundary would be a better choice when compared to that in the middle part of the corridor, since other pedestrians are less affected. In addition, in an environment with a relatively high crowd density, the affected pedestrians would usually experience significant decrease in velocity and obvious deviation in their trajectory. For pedestrians in the same lane with the temporary obstacle, it is obvious that the person right behind the pedestrian would be the most affected. With the increase in the sequence number after the temporary obstacle, the influence on velocity and target drift angle will gradually be reduced. The results of the present study can contribute to the relative modeling of pedestrian dynamics with fixed and temporary obstacles, and provide useful insights to crowd management.

Method to Determine Emergency Stop Position of Trains to Avoid Flash Floods

Method to Determine Emergency Stop Position of Trains to Avoid Flash Floods

Effect of shed geometry on starting mark of woven fabric

This paper aims to analyze the formation of starting mark on loom and the effect of shed geometry formed by warp yarns under various conditions. The actual cause of starting mark in woven fabric is variable pick spacing and cloth-fell displacement due to the relaxation nature of the warp yarn and fabric and the loom’s dynamic characteristics after restarting. Herein, nine woven fabrics of different constructions, compositions are used on an air-jet loom with a series of settings. Three shed angles were selected for specific warp yarn count, and other loom settings like heald frame height, back-rest height and depth, air pressure, take-up correction, automatic start offset, stop position were triggered to change the shed geometry, and then the effect of starting mark on fabric was checked. The pick spacings were then measured from fabric using a projection microscope, whereas various plots were generated utilizing the obtained data to check the pick spacing variation after a certain period of loom stoppage and restarting. Finally, the experimental results were analyzed with standard deviation, coefficient of variation % analysis using the IBM SPSS statistical program.