Kronologi dan Variabilitas Temuan Situs-Situs Kubur Batu di Pulau Sangihe Bagian Selatan

Kubur batu merupakan tinggalan megalitik yang sangat menonjol di Pulau Sangihe bagian selatan, sampai saat ini tercatat di 45 lokasi situs, 2 lokasi sumber bahan, dan jumlah kubur batu 699. Variabilitas temuan lainnya yang konteks dengan kubur batu, ditemukan pada saat survei yakni fragmen tembikar, keramik dan logam. Tulisan ini akan mengetengahkan tentang analisis laboratoris temuan tembikar, keramik dan logam tersebut. Kajian data berdasarkan penelitian survei dan ekskavasi dan kemudian dilanjutkan dengan analisis laboratoris melalui uji XRF dan sayatan tipis untuk temuan fragmen tembikar dan logam. Tembikar yang ditemukan berupa tembikar polos dengan bentuk wadah berupa periuk dan mangkuk. Berdasarkan analisis laboratorium dapat diketahui tembikar dari Pulau Sangihe kemungkinan merupakan tembikar produksi lokal.Analisis keramik diketahui berasal dari Cina, Cina Selatan, Eropa, dan Jepang. Kronologi keramik hasil penelitian dari abad ke 15–19 Masehi. Stone graves are prominent megalithic remains in the southern part of Sangihe Island. They are distributed in 45 site locations and 2 material source locations. The number of the stone graves is 699. Pottery, ceramic and metal fragments in the same context as the stone graves were found during the survey. This article will report the results of a laboratory analysis of the pottery, ceramic and metal findings. The data collected during the survey and excavation underwent a laboratory analysis. The pottery and metal fragments were tested by using the XRF technique and the thin section method. The pottery fragments found are plain pots and bowls. Based on the laboratory analysis, it is supposed that the pottery found in Sangihe Islands was locally produced. The analysis indicates that the ceramic fragments originated in China, South China, Europe and Japan. Chronologically, the ceramic fragments originated in the 15th-19th centuries.

New One-Dimensional Search Iteration Algorithm and Engineering Application

In structural optimization design, obtaining the optimal solution of the objective function is the key to optimal design, and one-dimensional search is one of the important methods for function optimization. The Golden Section method is the main method of one-dimensional search, which has better convergence and stability. Based on the solution of the Golden Section method, this paper proposes an efficient one-dimensional search algorithm, which has the advantages of fast convergence and good stability. An objective function calculation formula is introduced to compare and analyse this method with the Golden Section method, Newton method, and Fibonacci method. It is concluded that when the accuracy is set to 0.1, the new algorithm needs 3 iterations to obtain the target value. The Golden Section method takes 11 iterations, and the Fibonacci method requires 11 iterations. The Newton method cannot obtain the target value. When the accuracy is set to 0.01, the number of iterations of the new method is still the least. The optimized design of the T-section beam is introduced for engineering application research. When the accuracy is set to 0.1, the new method needs 3 iterations to obtain the target value and the Golden Section method requires 13 iterations. When the accuracy is set to 0.01, the new method requires 4 iterations and the Golden Section method requires 18 iterations. The new method has significant advantages in the one-dimensional search optimization problem.

ON THE ACCELERATION OF OPTIMIZATION METHODS FOR THE PROBLEM OF SYNTHESIS OF MULTILAYER OPTICAL COATINGS

Five ways to speed up the multidimensional search in order to solve the problem of synthesis of multilayer optical coatings by using the methods of zero and first orders have been considered. The first way is to use an analytical derivative for the target quality function of the multilayer coating. It allows us to calculate accurately (within the computer arithmetic) the value of the gradient of a smooth objective function and generalized gradient of a non-smooth objective one. The first way requires the same number of arithmetic operations as well as finite-difference methods of calculating the gradient and the generalized gradient. The second way is to use a speedy finding of the objective function gradient using the prefix- and suffix-arrays in the analytical method of calculating the gradient. This technique allows us to reduce the number of arithmetic operations thrice for large-scale problems. The third way is the use of tabulating the values of trigonometric functions to calculate the characteristic matrices. This technique reduces the execution time of multiplication operations of characteristic matrices ten times depending on the computer’s specifications. For some computer architectures, this advantage is more than 140 times. The fourth method is the use of the golden section method for the one-dimensional optimization in the problems of synthesis of optical coatings. In particular, when solving one partial problem it is shown that the ternary search method requires approximately 40% more time than the golden section method. The fifth way is to use the effective implementation of multiplication of two matrices. It lies in changing the order of the second and third cycles for the well-known method of multiplying two matrices and fixing in a common variable value of the element of the first matrix. This allows us to speed up significantly the multiplication operation of two matrices. For matrices having 1000 x 1000 dimension the acceleration is from 2 to 15 times, depending on the computer's specifications.

In-Process Height Displacement Measurement Using Crossed Line Beams for Process Control of Laser Wire Deposition

We propose the use of the line section method with crossed line beams for the process control of laser wire deposition. This method could be used to measure the height displacement in front of a laser spot when the processing direction changes. In laser processing, especially laser deposition of metal additive manufacturing, the laser process control technique that controls the processing parameters based on the measured height displacement in front of a laser processing spot is indispensable for high-accuracy processing. However, it was impossible to measure the height displacement in front of a processing laser spot in a processing route in which the processing direction changes as the measurement direction of the conventional light-section method comprising the use of a straight-line beam is restricted although the configuration is simple. In this paper, we present an in-process height displacement measurement system of the light-section method using two crossed line beams. This method could be used to measure the height displacement in a ±90° direction by projecting two crossed line beams from the side of a laser processing head with a simple configuration comprising the addition of one line laser to the conventional light-section method. The height displacement can be calculated from the projected position shift of the line beams irrespective of the measurement direction by changing the longitudinal position on the crossed line beams according to the measurement direction. In addition, the configuration of our proposed system is compact because the imaging system is integrated into the processing head. We could measure the height displacement at 2.8–4 mm in front of a laser processing spot according to the measurement direction by reducing the influence of intense thermal radiation. Moreover, we experimentally evaluated the height displacement measurement accuracy for various measurement directions. Finally, we evaluated continuous deposition in an “L” shape wherein the deposition direction was changed while using a laser wire direct energy deposition machine for the laser process control based on the in-process height displacement measurement result. We achieved highly accurate continuous deposition at the position wherein the processing direction changes despite the acceleration and deceleration of the stage by laser process control.

Pengaruh Self-Concept Terhadap Prestasi Akademik Mahasiswa Dimoderasi oleh Self-Efficacy

Latar Belakang: Prestasi akademik merupakan tingkat yang dicapai oleh siswa berdasarkan pengalaman belajarnya dalam suatu disiplin ilmu sebagai pencapaian tujuan dan kualifikasi yang ditetapkan di awal program pendidikan. Tujuan: Mengetahui dan menganalisis efek self-concept terhadap prestasi akademik mahasiswa dengan variabel moderasi self-efficacy. Metode: Menggunakan cross section method melalui kuesioner sebagai pengumpulan data. Populasi dan sampel dalam penelitian ini sebanyak 78 mahasiswa yang diperoleh dengan menggunakan teknik sampel jenuh. Data yang terkumpul kemudian dianalisis menggunakan teknik analisis data Moderated Regression Analysis (MRA). Hasil: Menunjukkan bahwa i) tingkat prestasi akademik berada pada kategori sangat memuaskan, self-concept dan self-efficacy berada pada kategori tinggi. ii) self-concept mempengaruhi prestasi akademik. iii) self-efficacy memoderasi pengaruh self-concept terhadap prestasi akademik. Kesimpulan: Bahwa terdapat pengaruh self-concept terhadap prestasi akademik mahasiswa, serta terdapat interaksi antara self-efficacy pada pengaruh self-concept terhadap prestasi akademik mahasiswa.