MENINGKATKAN PEMAHAMAN KONSEP MATEMATIKA MATERI OPERASI HITUNG BILANGAN BULAT MELALUI METODE DEMONSTRASI DENGAN MEDIA

ABSTRACTBased on the results of daily tests of mathematics subjects on the operation of counting integers, it shows the students' low level of mastery of the material. The factor of this is the learning process which is dominated by the teacher, tends to be lecture and the teacher only provides examples of questions. One way to improve students' understanding of concepts is to use demonstration methods with media. The purpose of this study was to improve understanding of the mathematical concept of integer arithmetic operations involving negative numbers in grade VI elementary school students using demonstration methods with media. This research is a classroom action research consisting of two cycles. The subjects of this study were the sixth grade students of SD Negeri 1 Tanjung Raya, totaling 36 students. Data collection techniques, namely by observation and tests. The results showed that the learning outcomes had increased, namely the results of the pre-cycle test 47%, the first cycle 64% and the second cycle to 92%. In addition, the activeness of students in participating in learning activities also increases. Thus it can be concluded that the use of the demonstration method is proven to improve the understanding of the mathematical concepts of the integer arithmetic operation material in students.Key words: integers, demonstration method, conceptual understanding.ABSTRAKBerdasarkan hasil ulangan harian mata pelajaran matematika tentang operasi hitung bilangan bulat menunjukkan rendahnya tingkat penguasaan materi siswa. Faktor terjadinya hal tersebut adalah proses pembelajaran yang didominasi oleh guru, cendrung bersifat ceramah dan guru hanya memberikan contoh-contoh soal. Salah satu cara untuk meningkatkan pemahaman konsep siswa adalah menggunakan metode demonstrasi dengan media. Tujuan penelitian ini adalah untuk meningkatkan pemahaman konsep matematika materi operasi hitung bilangan bulat yang melibatkan bilangan negatif pada siswa SD kelas VI menggunakan metode demonstrasi dengan media. Penelitian ini adalah penelitian tindakan kelas yang terdiri dari dua siklus. Subjek penelitian ini adalah siswa kelas VI SD Negeri 1 Tanjung Raya yang berjumlah 36 orang siswa. Teknik pengumpulan data yaitu dengan observasi dan tes. Hasil penelitian menunjukkan bahwa hasil pembelajaran mengalami peningkatan yaitu hasil tes prasiklus 47%, siklus pertama 64% dan siklus dua menjadi 92%. Selain itu keaktifan siswa dalam mengikuti kegitan belajar juga meningkat. Dengan demikian dapat disimpulkan bahwa penggunaan metode demonstrasi terbukti dapat meningkatkan pemahaman konsep matematika materi operasi hitung bilangan bulat  pada siswa. Kata Kunci : bilangan bulat, metode demonstrasi, pemahaman konsep

The role of photorespiration in abiotic stress conditions

Fotorespiracija je metabolički proces potaknut reakcijom oksigenacije enzima ribuloza-1,5- bisfosfat karboksilaze/oksigenaze. U toj se reakciji umjesto ugljikova dioksida, na ribulozu- 1,5-bisfosfat veže molekularni kisik. To dovodi do nastajanja 2-fosfoglikolata koji se reciklira tijekom fotorespiracije. Cilj je nastanak 3-fosfoglicerata, ugljikovog spoja koji može nastaviti svoj put u Calvin-Benson-Basshamovom ciklusu. Fotorespiracija troši energiju i redukcijske ekvivalente, stoga je smatrana rasipnim procesom. Međutim, ona ima važnu ulogu u odgovoru biljke na stresne uvjete. Izlaganjem stresnim uvjetima, dolazi do produkcije reaktivnih kisikovih oblika (ROS), u čijem uklanjanju sudjeluje niz staničnih mehanizama za obranu. U ovom radu predstavljena je uloga fotorespiracije u potrošnji viška energije što dovodi do smanjenja produkcije ROS u stanici i do sprječavanja fotoinhibicije. Nadalje, fotorespiracija kao integriran proces u biljnom metabolizmu sudjeluje u produkciji specifičnih metabolita i uklanjanju toksičnih intermedijera. Također, ima ulogu u prijenosu signala i induciranju obrambenog odgovora na stres, a inducira i aklimatizaciju biljaka na nepovoljne uvjete. Predstavljeni su rezultati istraživanja uloge fotorespiracije u određenim stresnim uvjetima kao što su suša, povišen salinitet, hladnoća te teški metali, a prikazani su i neki od pokusa s mutantama koji su doveli do boljeg razumijevanja uloge fotorespiracije.Photorespiration is a metabolic process initiated by the oxygenation reaction of ribulose-1,5- bisphosphate carboxylase/oxygenase. In this reaction, molecular oxygen binds to ribulose-1,5- bisphosphate instead of carbon dioxide. This leads to production of 2-phosphoglycolate which is recycled by photorespiration. The goal is the production of 3-phosphoglycerate, a carbon compound that can continue its way in the Calvin-Benson-Bassham cycle. Photorespiration consumes energy and reducing equivalents and was consequently considered as wasteful. However, it plays an important role in the response of plants to stressful conditions. When exposed to stress, plants produce reactive oxygen species (ROS), which are detoxified by numerous cellular mechanisms. This paper presents the role of photorespiration in dissipating excess energy which decreases the production of ROS in cell and prevents photoinhibition. Furthermore, as an integrated process in the plant metabolism, photorespiration participates in the production of specific metabolites and removal of toxic intermediates. It has a role in signals transduction and induction of stress defence response and it also induces acclimatization to unfavourable conditions. Research of the role of photorespiration in specific stressful conditions, such as drought, salinity, chilling and metal toxicity, is presented, including also experiments with metabolic mutants

An Algorithmic Approach for Stability of an Autonomous System

Many phenomena in biology can be modeled as a system of first order differential equations x = ax + by, y=cx+dy. An example of such a system is the prey-predator model. To interpret the results we have to obtain full information on the system of equations such as the stability of the equilibrium points of the system. This requires in depth knowledge of differential equations. The literature often emphasizes on the analytical methods to obtain results regarding the stability of the equilibrium points. This is possible to achieve for small systems such as a 2 x 2 system. The non-mathematician researchers often do not have the analytical tools to understand the model fully. Very often what they are interested in is the information regarding the critical points and their stability without going through the tedious mathematical analysis. This calls for user friendly tools for the non-mathematicians to use in order to answer their problem at hand. The objective of this research is to establish an algorithm to determine the stability of a more general system. By doing so we will be able to help those who are not familiar with analytical methods to establish stability of systems at hand The following algorithm is' employed in developing the software: L 1. Search for critical point is conducted. L2. Eigenvalues of the linear system are computed. These values are obtained from the characteristic equation IA - All = 0 , where A. is an eigenvalue and F or the nonlinear system, linearization process around the critical points are carried out. L3. Stability of system is determined. L4. Trajectory of the system is plotted in the phase plane. To develop the software we use the C programming language. It is hoped that the software developed will be of help to researchers in the field of mathematical biology to understand the concept of stability in their model

A simultaneous spam and phishing attack detection framework for short message service based on text mining approach

Short Messaging Service (SMS) is one type of many communication mediums that are used by scammers to send persuasive messages that will attract unwary recipients. In Malaysia, most sectors such as telecommunication, banking, government, healthcare, and private have taken the initiative to educate their clients about SMS scams. Unfortunately, many people still fall victim. Within the field of SMS detection, only the framework for a single attack detection for Spam has been studied. Phishing has never been studied. Existing detection frameworks are not suited to detect SMS Phishing because these attacks have their own specific behaviour and characteristic words. This gives rise to the need of producing a framework that is able to detect both attacks at the same time. This thesis addresses SMS Spam and Phishing attack detection framework development. 3 modules can be found in this framework, of which are Data Collection, Attack Profiling and Text Mining respectively. For Module 1, the data sets used in this research are from the UCI Machine Learning Repository, the Dublin Institute of Technology (DIT), British English SMS and Malay SMS. The Phishing Rule-Based algorithm is used to extract SMS Phishing. For Module 2, the SMS Attack Profiling algorithm is used in order to produce SMS Spam and Phishing words. The Text Mining module consists of several phases such as Tokenization, Lemmatization, Feature Selection and Classifier. These phases are done with the use of Rapidminer and the Weka data mining tool. Three (3) types of features are used in this framework, which are the Generic Features, Payload Features and Hybrid Features. All of these features are examined and the resulting performance metric used to compare the results is the rate of True Positive (TP) and Accuracy (A). There are four (4) set of results that were successfully obtained from this research. The first result shows that the extraction of SMS Phishing from the SMS Spam class contributes to four (4) enhanced datasets of the UCI Machine Learning Repository, the Dublin Institute of Technology (DIT), British English SMS and Malay SMS. The second results are the SMS Spam and Phishing attack profiling from the enhance UCI Machine Learning Repository, the Dublin Institute of Technology (DIT), British English SMS and Malay SMS. The third and fourth results are obtained from Feature Selection and Classifier phase where Eighty (80) experiments were done to examine the Generic Feature, Payload Features and Hybrid Features. There are five (5) Classification techniques used such as Naive Bayes, K-NN, Decision Tree, Random Tree and Decision Stump. The result of Hybrid Feature accuracy using Rapidminer and Naive Bayes technique is 77.47%, for K-NN: 78.56%, Decision Tree: 57.16%, Random Tree: 57.24% and Decision Stump: 57.16%. Meanwhile, by using Weka the Naive Bayes accuracy rate get 71.45%, K-NN: 81.64%, Decision Tree: 57.10%, Random Tree: 70.64% and Decision Stump: 60.19%. The experiments done using Rapidminer and Weka data mining tool because this is the first survey to detect SMS Spam and Phishing attack at the same time and the results are acceptable. Additionally, the proposed framework also can detect the attack simultaneously using text mining approaches

PENGARUH JENIS DAN JUMLAH POHON TERHADAP IKLIM MIKRO DI TAMAN PURBAKALA BUKIT SIGUNTANG KOTA PALEMBANG PROVINSI SUMATERA SELATAN

            Ruang terbuka hijau dapat mengatasi permasalahan lingkungan hidup perkotaan karena mampu memperbaiki iklim mikro. Tujuan penelitian ini adalah untuk mengetahui pengaruh jenis dan jumlah pohon terhadap kondisi iklim mikro di Taman Purbakala Bukit Siguntang, Kota Palembang, Provinsi Sumatera Selatan. Penelitian ini dilaksanakan pada bulan Juni sampai dengan Agustus 2016 di Taman Purbakala Bukit Siguntang. Penelitian ini menggunkanan metode pengamatan langsung di lapangan dengan intensitas sampling 3%. Hasil penelitian menunjukkan bahwa jenis dan jumlah pohon berpengaruh terhadap terbentuknya iklim mikro di Taman Purbakala Bukit Siguntang, Kota Palembang, Provinsi Sumatra Selatan. Pohon yang jumlahnya lebih banyak memberikan suhu yang lebih rendah, kelembaban udara relatif yang lebih tinggi, dan kecepatan angin yang lebih rendah dibandingkan dengan pohon yang jumlahnya sedikit.  Kondisi iklim mikro di bawah tajuk berbeda dengan kondisi iklim mikro di luar tajuk. Di bawah tajuk suhu udara lebih rendah, kelembaban udara lebih tinggi, dan kecepatan angin lebih rendah dibandingkan di luar tajuk

STRESS ANALYSIS USING FINITE ELEMENT METHOD ON SIALON/AISI 430 FERRITIC STAINLESS STEEL JOINT

Ceramic has many good characteristics for high temperature applications such as in heat exchangers. In the actual application of the ceramic to the structures, a ceramic-to-metal joint is unavoidable. This makes joining of ceramic to metal a critically important technology in advanced engineering. However, the fundamental problem in joining of metals and ceramics is the development of residual stresses which originated from the property mismatch between the ceramic and metal. A finite element analysis (FEA) using ANSYS was used to evaluate the residual stresses in the joints. In this analysis, stress analyses were conducted on sialon/AISI 430 joint. The joint was assumed to be perfectly bonded at the interface at 1200°C and stresses developed during cooling down to room temperature. Sequential coupled-field analysis was performed with PLANE55 and PLANE42. Model was simplified to two dimensional (2-D) problems, since its rotation about the axis of symmetry will generate the complete volume of the cylinder. It was found that the maximum tensile stress occur at the edge of sialon, close to the joint interface. The influence of thickness of sialon, diameter and joint design on the generation of stress in sialon was analyzed. Analyses were made to study the effect of each parameter on stress by varying it, for example, thickness of sialon, while fixing the other parameters. It was found that increasing thickness of sialon and diameter of the joint has resulted in increasing magnitude of tensile stress. The stresses can be reduced by employing symmetrical design joint and incorporating interlayer. The verification of the model was carried out by analytical calculation and comparison with literature review. The results of simulated stresses are in good agreement with the analytical method and literature review