Currently, almost all activities carried out by all parties are inseparable from the sound system. With the sound system, it is not necessary to speak loudly. There are several types of sound systems or models, ranging from the cheapest to the most expensive, with the usual quality up to good. However, there is a problem that can be obtained by a sound system that is of good quality or the usual quality, namely feedback from the speaker to the mic. Feedback will be very annoying because of the entry of sound from the speaker to the mic, which should be avoided. By using the inverse phase method and narrow bandpass filter, the simulation results can eliminate the feedback signal that is 100%. However, there are side effects on the band that occurs feedback, which is the reduction in the sound signal by the feedback power level that occurs between 30% - 100% that are in the frequency band range.

The ZIKV model presented in this article is developed by modifying \cite{Bonyah2016}’s model. The classical order is changed into fractional order model. The equilibrium points of the model are determined and the stability conditions of each equilibrium point have been done using Routh-Hurwitz conditions. Numerical simulation is presented to verify the result of stability analysis result. Numerical simulation is also used to shows the effect of the order $\alpha$ to the stability of the model’s equilibrium point.

This research constructs mathematic model for string vibration on Sasando that expressed as a second-order linear partial differential equation with u denote the vertical displacement experienced by the string at the point x at time t. Besides, the purpose of this research is to determine analytical solution using a method known as separation of variable. There are three analytical solutions from three cases based on constant coefficient values. Case 1 occurs when k d 2 > 4 n π l 2 1 2 c 2 + 2 c 2 l . Based on he simulation, the string produces a quarter wave within 3 seconds. This means the vibration wavelength 0.083 Hz. In this case the vertical displacement of the string is back to quiescent after vibrating to produce a quarter wave. Case 2 occurs when k d 2 = 4 n π l 2 1 2 c 2 + 2 c 2 l . The string produces 3.5 waves within 3 seconds, means the vibration wavelength is 1.67 Hz. In this case, the farthest vertical displacement (amplitude) become smaller drastically and back to quiescent. Case 3 occurs when k d 2 < 4 n π l 2 1 2 c 2 + 2 c 2 l . The vibration wavelength of the string is 2.83 Hz, with 7.5 waves within 3 seconds. The vertical displacement decreases periodically and back to quiescent at a certain time. Analysis of 2-dimensional graph for vertical displacement u(x,t) is done with n = 1,2,3,4,5 which is compared with profile of u(x,t) Gulla (2011). Based on results of the model were mentioned before, the mathematical model of string vibration on Sasando has the similar profile as Gulla (2011). For further, this research is suggested to perform a graph profile analysis of other cases that may arise with variation of parameter values.

String is one of mathematical modelling object has been studied in the world. In this paper, researchers focus on the construction analysis of the string motion model on Sasando. The purpose of the research is to determine the form of the string motion on Sasando musical instrument and validating the model. Construction analysis was done by identifying problems, variables, parameters, energies, and the forces occur on the string of Sasando. Based on the identifying results, mathematical model that represents the problem of string motion on Sasando expressed as a second-order linear partial differential equation with u denote the vertical displacement experienced by the string at the point x at time t. The first step of the validation test is simulations of mathematical models using Matlab. The result obtained shows the oscillatory motions and the string move towards the equilibrium position. It shows that mathematical model of the string motion on Sasando reliable to real case. However, the result of first step validation test are not sufficient to determine validity of the model and next step validation test are needed to complete this research.

Pendidikan sekolah menengah pertama (SMP) merupakan jenjang pendidikan wajib belajar pemerintah selama 9 tahun. Sehingga diperlukannya perhatian yang lebih tehadap seluruh sekolah SMP di Indonesia khususnya di Kota Pematangsiantar. Pelaksanaan proses pemberian bantuan Dinas Unit Pelaksanaan Teknis saat ini proses pengajuannya hanya berdasarkan satu kriteria saja yaitu tingkat kerusakan sekolah. Oleh karena itu dibutuhkan satu program yang dapat membantu Dinas UPTD dalam proses seleksi tersebut. Dalam perhitungan ini terdapat enam kriteria, yaitu: Skala kerusakan, jumlah siswa, kebutuhan kelas, prestasi akademik, prestasi non akademik, tahun mendapat bantuan terakhir. Berdasarkan permasalah tersebut, maka dalam penelitian dikembangkan Sistem Pendukung Keputusan dengan menggunakan metode Analytical Hierarchy Process (AHP) untuk mendapatkan sekolah mana yang layak mendapatkan bantuan pembangunan dengan bobot nilai tertinggi dan akan di uji dengan aplikasi Expert Choice 11.