Facial Flatness Indices: A Comparison of Two Methods of Assessment

Objectives: The objective of the study was to evaluate and compare facial flatness indices calculated from the trigonometric formula as opposed to those generated from the direct measurements on three-dimensional radiographs. Material and Methods: A total of 322 cone-beam computed tomography radiographs were digitized and three facial indices (frontal, simotic, and zygomaxillary) were assessed in two different methods and compared between different groups. Results: There was a discrepancy between facial flatness indices generated from the two different approaches. The highest difference was seen in the findings of the simotic index and the lowest for the zygomaxillary index. No statistically significant difference was displayed in the three formula-generated flatness indices between males and females and between growing and non-growing subjects (P > 0.05). The zygomaxillary index was the only measurement revealing no statistically significant difference in Class III sagittal malocclusions (t = −0.5 P = 0.621). The orthodontic application would yield to the same interpretations for both ways of indices calculation. Conclusion: The validity of the trigonometric formula used to appraise facial flatness indices might be questionable. The zygomaxillary index could be more clinically considered compared to the frontal and simotic indices.

Acoustic Source Localization and Navigation Robot

There are many areas of using acoustic localization technique. This technique is not only to locate a person, who is talking, but also could find them when they are in need. This can also be implemented in wild life photography, to locate the animals. In this technique, three microphones have been employed in the form of equilateral triangular pattern ,in which all these microphones detects the same sound .Using this information and trigonometric formula, the direction of sound has been calculated .The main objective of this project is calculate how precisely the position of sound source can be calculated using the technique mentioned above, while varying the distance and angle of the source .In order to explore the capabilities of TDOA and test the obtainable accuracy, a demonstrator was built. On a complete car chassis, three microphones were mounted and used to determine the direction towards the sound source. Thereafter, the robot rotated towards the sound source with an accelerator, keeping track of how much it had rotated. After this movement a comparison was made between the robot’s direction and the actual direction of the sound source. Finally an ultrasonic sensor was placed on the robot for obstacle detection whilst tracking the sound. The vehicle travelled straight forward until the ultrasonic sensor deemed that an object was too close. The results show that an increased distance yields a more accurate sound localization and that there are some angles in which the sound localization functioned better.

Pengembangan Media Pembelajaran Interaktif Berbasis Android Untuk Pemahaman Konsep Trigonometri

Tujuan dari penelitian ini adalah mengembangkan media pembelajaran interaktif berbasis android untuk memudahkan pemahaman konsep trigonometri. Penelitian ini merupakan penelitian pengembangan dengan pendekatan kualitatif yang didukung data kuantitatif. Model Pengembangan yang digunakan yaitu ADDIE. Karya inovasi ini dibuat dengan macromediaflash 8. Subjek dalam penelitian ini terdiri dari 8 siswa pada ujicoba kelompok kecil dan 30 siswa pada ujicoba kelompok besar. Teknik pengumpulan data yang digunakan yaitu angket dan wawancara. Teknik analisis data kualitatif dengan menggunakan model Miles Huberman.Hasilpengembangan diperoleh sebuah media pembelajaran yang dapat membantu siswa untuk mempermudah mengingat rumus trigonometri. Kata kunci: Media pembelajaran, android, konsep trigonometri Abstract [The Development of Interactive Android Based Learning Media to Facilitate Understanding of Trigonometric Concepts]. The purpose of this research is to develop interactive android based learning media to facilitate understanding of trigonometric concepts. This research is a development research with qualitative approach supported by quantitative data. Development model used is ADDIE. The innovation work was made with Macromedia Flash 8. The subjects in this study consisted of 8 students on a small group trial and 30 students on a large group trial. Data collection techniques used questionnaires and interviews. Qualitative data analysis technique using Miles Huberman model. The results of the development obtained a learning media that can help students to simplify remembering the trigonometric formula. Keywords: Learning media, android, the concept of trigonometry

Femoral imaging artifacts associated with dorsal recumbency craniocaudal radiographic positioning

Summary Objectives: To describe the radiographic length distortion associated with femoral tilt during cranio-caudal positioning. To describe a modified bisecting angle technique to alleviate image foreshortening. Methods: Five pairs of femurs were imaged. The femurs were tilted from 0 to 50 degrees and the X-ray anode was tilted from 0 to 40 degrees. Femoral length was measured on the resulting images. A geometric model depicting sagittal femoral positioning was described with two trigonometric formulas. Trigonometric formula 1 (TF1) was designed to predict apparent femoral length. Data generated by TF1 were compared to the cadaveric study results. Trigonometric formula 2 (TF2), based on the same model, was used to predict the ideal anode angle (iAA) to alleviate foreshortening. Unrelated to the model, a simplified linear formula (SF) was created to approximate the TF2. Data generated with the SF and the TF2 were compared. Results: When the femoral specimens were tilted to 20 degrees or greater, significant foreshortening was appreciated (p <0.001). Increasing the anode angle increased apparent length, eliminating foreshortening. Data generated by the TF1 agreed closely with the results of the cadaveric study (R2 = 0.999). The SF and the TF2 demonstrated close agreement and were able to predict an iAA consistent with the results of the cadaveric study. Clinical significance: A femoral tilt of 20 degrees or greater results in significant image foreshortening and may warrant alternate radiographic techniques. If the femur is tilted, adjusting the anode angle can alleviate femoral foreshortening.