Boundary driven waveguide arrays: Supratransmission and saddle-node bifurcation

In this report, we consider a semi-infinite discrete nonlinear Schr\"odinger equation driven at one edge by a driving force. The equation models the dynamics of coupled waveguide arrays. When the frequency of the forcing is in the allowed-band of the system, there will be a linear transmission of energy through the lattice. Yet, if the frequency is in the upper forbidden band, then there is a critical driving amplitude for a nonlinear tunneling, which is called supratransmission, of energy to occur. Here, we discuss mathematically the mechanism and the source of the supratransmission. By analyzing the existence and the stability of the rapidly decaying static discrete solitons of the system, we show rigorously that two of the static solitons emerge and disappear in a saddle-node bifurcation at a critical driving amplitude. One of the emerging solitons is always stable in its existence region and the other is always unstable. We argue that the critical amplitude for supratransmission is then the same as the critical driving amplitude of the saddle-node bifurcation. We consider as well the case of the forcing frequency in the lower forbidden band. It is discussed briefly that there is no supratransmission because in this case there is only one rapidly decaying static soliton that exists and is stable for any driving amplitude.Comment: Some figures are removed due to file size limi

MENINGKATKAN HASIL BELAJAR MATEMATIKA SISWA MELALUI MODEL KOOPERATIF TWO STAY TWO STRAY (TSTS) TAHUN PELAJARAN 2019/2020

Abstract: The success of a lesson can be measured by the achievement of student learning outcomes. Based on the preliminary test, it was found that 22 students (73.3%) were still under the KKM or who scored below 70. To improve learning outcomes, in this study the Two Stay Two Stray (TSTS) cooperative model was used. This type of research is classified as Classroom Action Research (PTK) with the implementation stages referring to the Kemmis and Taggart models. This research was planned in two cycles, including planning, action, observation and reflection. The subjects of this study were students of class VIIB Bangsalsari Junior High School 2019/2020, totaling 30 students. The test and observation method was used for data collection techniques, while the data analysis technique used comparative descriptive analysis (comparison) by comparing the results of pre-cycle, cycle 1 and cycle 2 and was calculated using a simple statistical formula. The results showed that the students' average score in the pre-cycle, cycle I and cycle II was 57.03; 71.97; and 85.57. Completeness of learning outcomes increased from 26.67% (8 of 30 children); 66.67% (20 of 30 children) and 90.00% (27 of 30 children). It can be concluded that the learning outcomes of class VIIB students of SMPN 3 Bangsalsari for the 2019/2020 academic year through the TSTS cooperative model can improve. Kata Kunci: Learning Outcome, cooperative Model, Two Stay Two Stra

PENINGKATAN KEMAMPUAN DESAIN GRAFIS INTERAKTIF DAN MENARIK BAGI SISWA MAN 1 SEMARANG MENGGUNAKAN CANVA

Perkembangan teknologi informasi tidak hanya berperan dalam bidang bidang perekonomian, tapi juga bidang pendidikan. Dewasa ini setiap siswa di sekolah mulai diajarkan pelajaran teknologi informasi salah satunya adalah desain. Hal ini dilakukan agar dapat memenuhi permintaan industri akan generasi yang memiliki kemampuan presentasi yang baik dan interaktif dengan menerapkan teknologi informasi. Perkembangan teknologi semakin pesat dan maju, setiap orang diharapkan dapat mengerti teknologi sebagai penunjang segala aktivitas yang ada, begitupun dalam ranah pendidikan. Guru serta peserta didik dapat memanfaatkan media pembelajaran berbasis teknologi salah satunya ialah aplikasi Canva. Canva merupakan aplikasi berbasis online dengan menyediakan desain menarik berupa template, fitu-fitur, dan kategori-kategori yang diberikan di dalamnya. Dengan desain yang beragam dan menarik, membuat proses pembelajaran menjadi tidak membosankan. Dengan menggunakan aplikasi Canva, guru dan siswa dapat mengajarkan ilmu pengetahuan, kreativitas, serta keterampilan yang akan didapatkan untuk peserta didik, sehingga media ini juga dapat dimanfaatkan dalam media presentasi. Dan kususnya para siswa dapat membuat presentasi yang interaktif dengan menggunakan canva

Seguridad marina: estudio de caso sobre el cumplimiento del equipo de seguridad para la seguridad del buque

This study aimed to identify the fulfillment of safety equipment and its effect towards ship safety. This study was conducted at some harbors in Indonesia such as Soekarno Hatta Harbor at Makassar, Tanjung Perak Harbor at Surabaya and Tanjung Priok harbor at Jakarta. The sampling technique was Purposive sampling. Data were collected by questioners with Likert model scale. The obtained data then was being analysed using descriptive statistic and inferential statistic consisted of regression analysis and correlation. The result showed that there were positive and significant effects between safety equipment fulfilment and sailor ship safety. The regression equation was. Moreover, safety equipment fulfilment had strong effects toward sailor ship safety with 0.753 coefficient correlation 55.3% contribution. Further, the other 44.7% was influenced by other variables.Este estudo teve como objetivo identificar o cumprimento de equipamentos de segurança e seus efeitos para a segurança do navio. O estudo foi realizado em alguns portos da Indonésia, como Soekarno Hatta Harbour em Makassar, Tanjung Perak Harbour em Surabaya e Tanjung Priok porto em Jacarta. A técnica de amostragem foi amostragem intencional. Os dados foram coletados e tabulados utilizando-se a escala do modelo Likert. Os dados obtidos foram então analisados por estatística descritiva e estatística inferencial composta por análise de regressão e correlação. O resultado mostrou que houve efeitos positivos e significativos entre o cumprimento dos equipamentos de segurança e a segurança dos navios de marinheiro. A equação de regressão foi Y'= 2.421 + 0.753X. Além disso, o cumprimento dos equipamentos de segurança teve fortes efeitos em relação à segurança dos navios de marinheiro, com 0.753 correlação de coeficiente de 55.3% de contribuição. Além disso, os outros 44.7% foram influenciados por outras variáveis.Este estudio tuvo como objetivo identificar el cumplimiento de los equipos de seguridad y su efecto hacia la seguridad del barco. Este estudio se realizó en algunos puertos de Indonesia, como el puerto de Soekarno Hatta en Makassar, el puerto de Tanjung Perak en Surabaya y el puerto de Tanjung Priok en Yakarta. La técnica de muestreo fue el muestreo intencional. Los datos fueron recolectados por los interrogadores con la escala del modelo de Likert. Los datos obtenidos se analizaron mediante estadística descriptiva y la estadística inferencial consistió en análisis de regresión y correlación. El resultado mostró que hubo efectos positivos y significativos entre el cumplimiento del equipo de seguridad y la seguridad del buque marinero. La ecuación de regresión fue Y ^ '= 2,421 + 0,753X. Además, el cumplimiento del equipo de seguridad tuvo fuertes efectos en la seguridad de los buques marinos con una correlación de 0.753 coeficientes con una contribución del 55.3%. Además, el otro 44.7% fue influenciado por otras variables