Jurnal Online Universitas Islam Sumatera Utara
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PENGARUH MODEL PEMBELAJARAN PROBLEM SOLVING BERBANTUAN APLIKASI AUTOGRAPH TERHADAP KEMAMPUAN REPRESENTASI MATEMATIS SISWA KELAS VIII UPTD SMP NEGERI 1 PEMATANGSIANTAR
Full text linkThis study aims to examine the effect of the Autograph application-assisted Problem Solving learning model on the mathematical representation abilities of students in Grade VIII at UPTD SMP Negeri 1 Pematangsiantar. This study uses a quantitative experimental research design. Quantitative research is objective in terms of data collection, quantitative data analysis, and testing using statistical methods. This study will be conducted in class VIII of SMP Negeri 1 Pematangsiantar. The sampling technique used by the researcher to determine the sample in this study is cluster random sampling. Based on the results of data analysis and discussion, it can be concluded that there is a positive and significant effect of the use of the problem-solving learning model on the mathematical representation abilities of students in class VIII UPTD SMP Negeri 1 Pematangsiantar. This effect is shown by the correlation value between variables (R) of 0.945 and the regression equation ̂ = −4.357 + 0.473 with a value of = 0.473. Based on the t-test results, it was found that there was a significant effect and the coefficient of determination showed a positive effect of 89.3%
ANALISA PERFORMA SEPEDA MOTOR PCX 150 INJEKSI STANDARD DENGAN PCX 150 INJEKSI MENGGUNAKAN HYBIRD SYSTEM PARALLEL DAN MOTOR ASSIST BERBAHAN BAKAR PERTAMAX DENGAN MENERAPKAN PERAWATAN PREVENTIVE MAINTENANCE
Full text linkTujuan penelitian ini adalah untuk menganalisis Analisa Performa Sepeda Motor Pcx 150 Injeksi Standard Dengan Pcx 150 Injeksi Menggunakan Hybird System Parallel Dan Motor Assist Berbahan Bakar Pertamax Dengan Menerapkan Perawatan Preventive Maintenance, Metode yang digunakan adalah eksperimen yang dilakukan pada Motor Honda PCX 150 FI. Torsi engine yangdihasilkan oleh motor Honda PCX 150 F1 lebih besar dengan menggunakan Hybrid yaitu 18,4 Nm pada putaran engine 6000 rpm, sedangkan Torsi engine terendahyaitu 8,3 Nm pada putaran engine 2000 rpm menggunakan bahan bakar Pertmax. Daya engine yang dihasilkan oleh motor Honda PCX 150 F1 lebih besar dengan menggunakan Hybrid yaitu 11,8 hp pada putaran engine 6000 rpm, sedangkan Daya engine terendah yaitu 1,8 hp pada putaran engine 2000 rpm menggunakan bahan bakar Pertamax
Penggunaan Converter Frekuensi Untuk Mengatur Putaran Motor Induksi
Full text linkFrekuensi jala-jala tenaga listrik yang digunakan di Indonesia yaitu 50 Hz, pada frekuensi ini jika daya dihubungkan langsung pada kumparan stator motor induksi 4 kutub, maka putaran sinkron motor adalah 1500 rpm. Mengingat perlunya pengaturan putaran motor untuk suatu keperluan tertentu maka salah satu cara yang digunakan adalah dengan menggunakan rangkaian perubah frekuensi yang terlebih dahulu melalui tahap penyearah. Prinsip operasinya : terlebih dahulu supply daya 3 phasa 50 Hz dari jala-jala disearahkan melalui penyearah tiga fasa terkendali. Arus searah yang telah diratakan tersebut diubah kembali menjadi bentuk daya bolak balik melalui rangkaian inverter jembatan 3 phasa. Daya dengan frekuensi yang variable diperoleh dengan cara memperlambat atau mempercepat perioda pulsa yang memicu SCR yang diatur melalui rangkaian pengontrol penyalaan gate. Pengaturan frekuensi dapat dilakukan dengan menggunakan konverter frekuensi dimana arus bolak balik diubah terlebih dahulu menjadi arus searah dan pada bagian akhir dari proses diubah kembali menjadi arus bolak-balik dengan fekuensi yang dapat diatur. Dalam pengaturan putaran motor induksi dengan mengatur frekuensi ini harus diikuti dengan pengaturan tegangan, hal ini dimaksudkan agar fluksi yang dihasilkan mempunyai harga konstan, pengaturan fekuensi dan pengaturan tegangan yang sebanding ini maka pada pengaturan penyalaan inverter digunakan sistem pengaturan modulasi lebar pulsa (Pulsa Width Modulation). Sistem ini bekerja mengatur lebar pulsa sebagai penyalaan inverter untuk setiap setengah siklus gelombang sinus. Banyaknya pulsa yang dihasilkan tiap setengah gelombang sinus menentukan besarnya frekuensi dan tegangan output yang dihasilkan inverter. Jadi dengan mengatur lebar pulsa untuk penyalaan inverer, frekuensi dan tegangan dapat diatur sekaligus dan akan membangkitkan besar fluksi yang konstan pada celah udara
Perbandingan Hasil Monitoring Daya Listrik pada Rumah Tangga dengan PZEM-004T di LCD dan di Aplikasi Blynk
Full text linkPenggunaan daya listrik di rumah tangga selama ini hanya dapat dilihat melalui alat ukur kWh meter yang didistribusikan oleh PLN. Penggunaan alat tersebut tidak memberikan informasi tentang berapa besar daya listrik yang digunakan. kWh meter hanya menunjukkan jumlah daya kumulatif yang terpakai. Oleh karena itu, diperlukan alat yang dapat memperlihatkan penggunaan daya listrik secara real-time, sehingga memudahkan pengguna untuk memantau konsumsi energi listrik. Tujuan penelitian adalah membandingkan hasil memonitoring daya listrik rumah tangga menggunakan arduino NodeMCU ESP8266 secara real-time. Metode yang digunakan dalam penelitian ini terdiri dari 4 tahapan, yaitu : 1). Pemilihan peralatan software dan hardware, 2). Perancangan sistem, 3). Pembuatan program, dan 4). Pengujian alat. Hasil dari pengujian alat menggunakan beban berupa setrika, kipas angin, dispenser, dan charger handphone. Alat bekerja dengan baik mampu membaca daya listrik di LCD dan di Aplikaso Blynk
Pengaruh Intensitas Cahaya Matahari Terhadap Tegangan Panel Surya
Full text linkPenggunaan energy terbarukan merupakan alternative untuk mengurangi permintaan energy ke PLN dan pengoptimalan potensi alam. Sel surya merupakan teknologi yang mengubah cahaya matahari menjadi energy listrik. Tujuan penelitian ini adalah mengetahui hubungan intensitas cahaya matahari terhadap tegangan pada sebuah panel sel surya. Metode penelitian ini adalah pengukuran intensitas matahari secara real dan pengukuran daya keluaran panel sel surya tersebut, adapun bahan yang digunakan adalah lumen meter digunakan untuk mengukur intensitas cahaya matahari, multimeter digunakan untuk mengukur tegangan dan arus, battery charge regulator dengan kapasitas 10 A, Panel sel surya dengan kapasitas 100 Wp, dan battery 80 Ah. Pengujian dilakukan selama 6 hari, setiap hari pengujian dimulai dari jam 08.00 – 18.00. Hasil penelitian menunjukkan bahwa intensitas cahaya matahari tertinggi terjadi antara jam 11.00 – 13.00 dengan nilai intensitas cahaya matahari sebesar 98.700 lux – 118.400 lux, sedangkan daya keluaran sel surya tertinggi sebesar 16,86 watt dengan intensitas cahaya matahari terukur 118.400 lu
CHARACTER AND THE STRUGGLE FOR IVILIZATION IN WILLIAM GOLDING'S LORD OF THE FLIES
Full text linkWilliam Golding's Lord of the Flies (1954) presents a profound exploration of human nature under duress, centering on the collapse of social order and the descent into primal savagery. This study employs a descriptive qualitative method to conduct a character analysis of the novel's protagonist, Ralph, focusing on the intrinsic qualities that define his struggle for survival and the preservation of civilization. Through a close reading of the text, this paper identifies and examines four cardinal traits—leadership, charisma, organizational prowess, and civility—that constitute Ralph's character. The analysis demonstrates that these traits are not merely descriptive but are the fundamental engines of his resistance against the antagonistic force, represented by Jack, which embodies chaos and violence. The findings reveal that Ralph's struggle is multifaceted: it is a physical battle for survival, a psychological fight against despair, and an ideological conflict for the soul of the community. Ultimately, this paper argues that Ralph's characterization serves as Golding's central argument for the fragility of civilization, which must be consciously and courageously upheld through rational principles, democratic leadership, and moral fortitude, even in the face of overwhelming barbarism. His survival is a testament to the resilience of these values
INTEGRATING DUOLINGO ENGLISH TEST (FREE PRACTICE) IN EFL SPEAKING INSTRUCTION: A QUASI-EXPERIMENTAL STUDY AT UNIVERSITAS NEGERI MEDAN
Full text linkEnglish speaking ability, a primary competency for English Education students, is often hindered by limited practice, lack of confidence, and minimal independent learning media. This study investigates the effectiveness of the Duolingo English Test (Free Practice) platform as a digital learning medium within the Receptive Oral Language Skills course to enhance students' English speaking abilities. This study uses a quantitative approach with a one-group quasi-experimental design, involving a pre-test and post-test to measure improvement before and after the intervention. The intervention consisted of routine practice using the Duolingo platform and supplementary materials from the "Teacher Luke" YouTube channel. Quantitative data from test scores were analyzed using a paired sample t-test, while qualitative data from questionnaires were used to explore student perceptions. The results of this study are expected to provide an effective, flexible learning solution suited for students in the digital era. The conclusion indicates that the strategic use of digital media like the Duolingo English Test can be encouraged in speaking skills instruction at the university level
PATTERNS AND AWARENESS OF CODE-MIXING AMONG INDONESIAN YOUTHS IN AN ENGLISH-SPEAKING COMMUNITY: A SOCIOLINGUISTIC ANALYSIS
Full text linkThis qualitative study investigates the patterns and underlying factors of code-mixing (CM) among Indonesian youths in Aaron's English-Speaking Club, a community dedicated to practicing English in Medan, Indonesia. Employing a grounded theory approach by Charmaz (2016), the research involved in-depth interviews with ten club members, selected via probability sampling. The conversations were analyzed to quantify the frequency of CM (the insertion of Indonesian words into English discourse) and to identify the sociolinguistic factors influencing this phenomenon using the framework of Holmes (1992). Findings reveal that all participants engaged in CM, with percentages ranging from 0.52% to 24.34% of their total words. The analysis indicates that CM is not an indicator of low proficiency but a strategic, communicative resource. Key factors influencing CM included occupation, cultural attitude, and regional background. Notably, participants were initially unaware of the linguistic concepts of CM and code-switching (CS), but upon explanation, all identified more strongly with CM than CS in their typical language use. The study concludes that CM is a natural and prevalent feature of bilingual communication among these youths, reflecting their dynamic linguistic identity and the specific social context of their English practice community. It recommends increased metalinguistic awareness to empower speakers in their bilingual journey
KARO DIALECTAL VARIATION IN TANAH KARO: A LEXICAL AND PHONOLOGICAL SOCIOLINGUISTIC ANALYSIS
Full text linkLanguage holds the memory of a community and shapes how people understand themselves, their landscape, and their cultural belonging. This study investigates dialectal variation in the Karo language of Tanah Karo, North Sumatra, through a lexical and phonological sociolinguistic framework. Using a descriptive qualitative design supported by dialectological procedures, the research analyzes 200 Swadesh-based lexical items and natural speech data collected from six native speakers representing three major dialect regions: Julu (Tigapanah), Teruh Deleng (Tiganderket), and Singalor Lau (Tigabinanga). Structured interviews, direct observation, and audio-recorded elicitation sessions formed the basis of the dataset. Findings show that while the dialects remain mutually intelligible, they exhibit systematic micro-variations in vowel realization, lexical selection, and morphophonemic structure. Tigabinanga displays the most consistent vowel fronting and several unique lexical items, whereas Tigapanah and Tiganderket share closer phonological and lexical affinities. These patterns reflect the influence of geographical separation, inter-village communication, and long-standing cultural identity. The study contributes to the documentation of Indonesia’s regional languages and underscores the importance of preserving dialectal diversity. Further research using acoustic phonetics or quantitative dialectometry is recommended to deepen the understanding of phonological distance within the Karo speech community
A SEMANTIC ANALYSIS OF COGNITIVE MEANING IN BOB MARLEY’S SONG LYRICS
Full text linkThis study explores the cognitive meanings in Bob Marley’s selected songs—One Love, Three Little Birds, and Could You Be Loved—through a semantic approach. Employing a qualitative descriptive method, it identifies meaning relations such as synonymy, antonymy, hyponymy, and polysemy within the lyrics. Findings reveal that Marley’s songs embody profound cognitive meanings, reflecting human experience, social values, and the struggle for justice. His poetic and symbolic language communicates universal messages of peace, solidarity, and resilience. The study demonstrates how cognitive semantics can illuminate the intersection of language, music, and social consciousness. Through a qualitative descriptive method and semantic analysis, the study identifies various meaning relations such as synonymy, antonymy, hyponymy, and polysemy that are embedded within the lyrics. Findings reveal that Marley’s songs embody profound cognitive meanings, reflecting human experience, social values, and the struggle for justice. His poetic and symbolic language communicates universal messages of peace, solidarity, and resilience. The study demonstrates how cognitive semantics can illuminate the intersection of language, music, and social consciousness