Influence of Tool Length and Profile Errors on the Inaccuracy of Cubic-Machining Test Results

A cubic-machining test has been proposed to evaluate the geometric errors of rotary axes in five-axis machine tools using a 3 × 3 zone area in the same plane with different tool postures. However, as only the height deviation among the machining zones is detected by evaluating the test results, the machining test results are expected to be affected by some error parameters of tool sides, such as tool length and profile errors, and there is no research investigation on how the tool side error influences the cubic-machining test accuracy. In this study, machining inaccuracies caused by tool length and tool profile errors were investigated. The machining error caused by tool length error was formulated, and an intentional tool length error was introduced in the simulations and actual machining tests. As a result, the formulated and simulated influence of tool length error agreed with the actual machining results. Moreover, it was confirmed that the difference between the simulation result and the actual machining result can be explained by the influence of the tool profile error. This indicates that the accuracy of the cubic-machining test is directly affected by tool side errors.

Agreement between rhinomanometry and computed tomography-based computational fluid dynamics

Purpose Active anterior rhinomanometry (AAR) and computed tomography (CT) are standardized methods for the evaluation of nasal obstruction. Recent attempts to correlate AAR with CT-based computational fluid dynamics (CFD) have been controversial. We aimed to investigate this correlation and agreement based on an in-house developed procedure. Methods In a pilot study, we retrospectively examined five subjects scheduled for septoplasty, along with preoperative digital volume tomography and AAR. The simulation was performed with Sailfish CFD, a lattice Boltzmann code. We examined the correlation and agreement of pressure derived from AAR (RhinoPress) and simulation (SimPress) and these of resistance during inspiration by 150 Pa pressure drop derived from AAR (RhinoRes150) and simulation (SimRes150). For investigation of correlation between pressures and between resistances, a univariate analysis of variance and a Pearson’s correlation were performed, respectively. For investigation of agreement, the Bland–Altman method was used. Results The correlation coefficient between RhinoPress and SimPress was r = 0.93 (p < 0.001). RhinoPress was similar to SimPress in the less obstructed nasal side and two times greater than SimPress in the more obstructed nasal side. A moderate correlation was found between RhinoRes150 and SimRes150 (r = 0.65; p = 0.041). Conclusion The simulation of rhinomanometry pressure by CT-based CFD seems more feasible with the lattice Boltzmann code in the less obstructed nasal side. In the more obstructed nasal side, error rates of up to 100% were encountered. Our results imply that the pressure and resistance derived from CT-based CFD and AAR were similar, yet not same.

FPGA implementation of RGB image encryption and decryption using DNA cryptography

The rapid growth in digitization transmission of information in the form of RGB image. During the process transmission of the image in a channel, some data may be degraded due to noise. At receiver side error in data has to be detected and corrected. Hamming code is one of the popular techniques for error detection and correction. In this paper new algorithm proposed for encryption and decryption of RGB image with DNA cryptography and hamming code for secure transmission, and correction. this algorithm first encodes data to hamming code and encrypted to DNA code. Two-bit error detection and correction for each pixel of the image can be performed.DNA code improves security and use of the Hamming code for error detection and correction. For the image of size 256*256 pixel image, it corrects up to 2*256*256 bits in RGB image. The RGB image encryption and decryption design using Verilog and implemented using FPGA (Field Programmable Gate Array).

How to avoid wrong-level and wrong-side errors in lumbar microdiscectomy

Object When performing a single-level lumbar decompressive procedure, the first of all errors to avoid is operating at the wrong level or on the wrong side. In this report the authors describe their method of trying to minimize this potential risk. Methods A 3-step procedure—the IRACE (intraoperative radiograph and confirming exclamation) method—was designed and adopted for single-level lumbar decompressive surgeries. Before skin incision, a wire is placed in the spinous process and lateral fluoroscopy is performed. Subsequently and also before skin incision, the assistant nurse provides oral confirmation of the level and side. Additional fluoroscopic control is provided before starting the laminotomy. The clinical records of 818 consecutive patients who had undergone lumbar microdiscectomy as an initial operation between 2001 and 2005 were retrospectively reviewed. Surgical charts as well as clinical and neuroimaging follow-up data were analyzed. Results No patient clinically and/or neuroradiologically demonstrated a level or side error. In 1 (0.12%) of 818 surgical procedures a wrong level was initially explored. The absence of frank disc herniation and the discrepancy with preoperative neuroimages led to fluoroscopic control in this case, and the correct level was then approached. No clinically apparent method-related complications were registered. Conclusions The problem of an incorrect level or side in lumbar surgery remains unresolved. The authors propose a useful and easily applied procedure to reduce such a risk. Larger studies comparing different methods of avoiding such errors will probably lead to the definition and wide adoption of a surgical behavior aiming to reach a near-zero error rate.