Tongue Postures and Tongue Centers: A Study of Acoustic-Articulatory Correspondences Across Different Head Angles

Recent research on body and head positions has shown that postural changes may induce varying degrees of changes on acoustic speech signals and articulatory gestures. While the preservation of formant profiles across different postures is suitably accounted for by the two-tube model and perturbation theory, it remains unclear whether it is resulted from the accommodation of tongue postures. Specifically, whether the tongue accommodates the changes in head angle to maintain the target acoustics is yet to be determined. The present study examines vowel acoustics and their correspondence with the articulatory maneuvers of the tongue, including both tongue postures and movements of the tongue center, across different head angles. The results show that vowel acoustics, including pitch and formants, are largely unaffected by upward or downward tilting of the head. These preserved acoustics may be attributed to the lingual gestures that compensate for the effects of gravity. Our results also reveal that the tongue postures in response to head movements appear to be vowel-dependent, and the tongue center may serve as an underlying drive that covariates with the head angle changes. These results imply a close relationship between vowel acoustics and tongue postures as well as a target-oriented strategy for different head angles.

PEMBUATAN JIG PROSES PRE DRILL MODEL B74 GUNA MENURUNKAN REJECT CONCENTRIC PADA LINI PRODUKSI PENGECORAN OUTER TUBE DI PT KAYABA INDONESIA

Salah satu produk PT Kayaba Indonesia adalah front fork assy yang mana didalamnya terdapat part yaitu outer tube. Proses awal pembuatan outer tube adalah proses pengecoran. Ada 2 macam mesin pengecoran gravitasi yang digunakan oleh PT Kayaba Indonesia yaitu mesin pengecoran gravitasi existing tipe core dan mesin pengecoran gravitasi tilting tipe solid. Model B74 salah satu produk yang menggunakan mesin pengecoran gravitasi tilting sehingga model B74 termasuk ke dalam tipe solid. Sebelum masuk ke proses machining, outer tube model B74 harus melewati proses Pre drill untuk membuat diameter dalam agar memudahkan proses selanjutnya pada lini pemesinan. Saat ini proses Pre drill model B74 memiliki masalah reject concentric yang cukup tinggi, yaitu 7%. Proses penurunkan reject concentric proses Pre-drill model B74 telah dilakukan Penulis bersama tim mekanik proses pengecoran meliputi upaya memindahkan proses Pre-drill model B74 ke mesin macod dan pembuatan jig untuk mendukung proses tersebut. Perbaikan yang dilakukan berhasil menurunkan reject yang terjadi, dari 7% dari 8.812 set menjadi 1,4% dari 3.360 set. Selain itu perbaikan ini juga menaikan kuantitas produksi sehingga yang awalnya membutuhkan 2 shift untuk mencapai target menjadi cukup hanya 1 shift dengan hari kerja normal.

Iterative Metal Artifact Reduction (iMAR) of the Non-adhesive Liquid Embolic Agent Onyx in Computed Tomography

Background A drawback of Onyx, one of the most used embolic agents for endovascular embolization of intracranial arteriovenous malformations (AVM), is the generation of imaging artifacts (IA) in computed tomography (CT). Since these artifacts can represent an obstacle for the detection of periprocedural bleeding, this study investigated the effect of artifact reduction by an iterative metal artifact reduction (iMAR) software in CT in a brain phantom. Methods Two different in vitro models with two-dimensional tube and three-dimensional AVM-like configuration were filled with Onyx 18. The models were inserted into a brain imaging phantom and images with (n = 5) and without (n = 10) an experimental hemorrhage adjacent were acquired. Afterwards, the iMAR algorithm was applied for artifact reduction. The IAs of the original and the post-processed images were graded quantitatively and qualitatively. Moreover, qualitative definition of the experimental hemorrhage was investigated. Results Comparing the IAs of the original and the post-processed CT images, quantitative and qualitative analysis showed a lower degree of IAs in the post-processed images, i.e. quantitative analysis: 2D tube model: 23.92 ± 8.02 Hounsfield units (HU; no iMAR; mean ± standard deviation) vs. 5.93 ± 0.43 HU (with iMAR; p < 0.001); qualitative analysis: 3D AVM model: 4.93 ± 0.18 vs. 3.40 ± 0.48 (p < 0.001). Furthermore, definition of the experimental hemorrhage was better in the post-processed images of both in vitro models (2D tube model: p = 0.004; 3D AVM model: p = 0.002). Conclusion The iMAR algorithm can significantly reduce the IAs evoked by Onyx 18 in CT. Applying iMAR could thus improve the accuracy of postprocedural CT imaging after embolization with Onyx in clinical practice.

Tube-model predictive control based on sum of squares for hypersonic vehicle with state-dependent input constraints

In this paper, tube-model predictive control based on the sum of squares technique is developed for hypersonic vehicles with state-dependent input constraints. Firstly, the longitudinal non-linear model in the presence of uncertain parameters is transformed into the polytopic linear parameter varying model with bounded disturbance by feedback linearization. Then the actual input constraints are converted to the virtual state-dependent input constraints in linear multivariable polynomial. A composite feedback control law based on tube-model predictive control is designed into a convex combination of unconstrained and constrained control. The real control law can be obtained by inversion. The sum of squares technique is used to transform the polynomial constraints into the convex matrix sum of squares condition via linear matrix inequality. Finally, simulation results verify the effectiveness of the proposed controller.