Abstract--Attendance is the documentation of presence and activity in institution. A software has been made to monitor the attendance using face recognition. The software uses camera to capture the image and works on any background color. The aim of this paper is to calculate its performance with sensitivity, specificity, and accuracy using Eigenface Algorithm and Principal Component Analysis (PCA) method. Face recognition in this paper is based on Eigenface algorithm, using pixel information from images captured by webcam. The image is represented using PCA method. The software is tested using different expressions and accessories in object's face. The performance of the software indicates 73.33% sensitivity, 52.17% specificity, and 86.67% accuracy. The successful rate in identifying the face for distance testing is 70%, while successful rate of 85% is achieved for object wearing eyeglasses and veil (jilbab). Furthermore, the successful rate for various expression is 85.33%.Intisari--Presensi adalah pendataan kehadiran atau aktivitas pada suatu institusi. Aplikasi komputer yang dikembangkan pada sistem presensi digunakan untuk mengenali wajah seseorang dengan kamera tanpa menentukan warna latar belakang pada citra. Makalah ini bertujuan untuk mengetahui nilai sensivisitas, kekhususan, dan akurasi dari sebuah citra pada sistem presensi menggunakan algoritme eigenface dan metode Principal Component Analysis (PCA). Sistem pengenalan wajah pada makalah ini berbasis algoritme eigenface, berdasarkan citra yang dihasilkan melalui webcam dan informasi dari piksel citra. Kemudian, citra direpresentasikan menggunakan metode PCA. Citra dideteksi dengan mengekstraksi mimik wajah dan penggunaan aksesoris pada area wajah. Sistem presensi yang diimplementasikan dengan deteksi wajah berhasil dilakukan dengan pengujian berbagai ekspresi, aksesoris, jarak, dan pada latar belakang yang kompleks. Tingkat keberhasilan sistem ditunjukkan dengan nilai sensivisitas 73,33%, kekhususan 52,17%, dan akurasi 86,67%. Tingkat keberhasilan proses identifikasi pada pengujian jarak adalah sebesar 70%, sedangkan ketika menggunakan aksesoris kacamata dan kerudung sebesar 85%, dan proses identifikasi dengan berbagai ekspresi sebesar 85,33%.Kata Kunci -Sistem presensi, Deteksi wajah, Eigenface, Principal Component Analysis.

Abstrak ---Presensi adalah suatu pendataan kehadiran, bagian dari pelaporan aktivitas suatu institusi, atau komponen institusi itu sendiri yang berisi data-data kehadiran yang disusun dan diatur sedemikian rupa sehingga mudah untuk dicari dan dipergunakan apabila sewaktu-waktu diperlukan oleh pihak yang berkepentingan. Aplikasi komputer yang dikembangkan pada sistem presensi adalah aplikasi komputer yang dapat mengenali wajah seseorang hanya dengan menggunakan webcam. Pengenalan wajah dalam penelitian ini menggunakan sebuah webcam untuk menangkap suatu citra kondisi ruangan pada waktu tertentu yang kemudian diidentifikasi wajah yang ada. Beberapa metode yang digunakan dalam penelitian disini adalah metode Dynamic Times Wrapping ( DTW ) , Principal Component Analysis (PCA) dan Gabor Wavelet. Pada sistem ini, digunakan pengujian dengan ekspresi citra wajah normal. Tingkat keberhasilan pengenalan dengan citra wajah ekspresi normal menggunakan metode DTW sebesar 80%, PCA 100 % dan Gabor wavelet 97 %. Kata kunci: Presensi, PCA, DTW, Eigenface, Gabor Wavelet.Abstract ---Presensi is a logging attendance, part of activity reporting an institution, or a component institution itself which contains the presence data compiled and arranged so that it is easy to search for and used when required at any time by the parties concerned. Computer application developed in the presensi system is a computer application that can recognize a person's face using only a webcam. Face recognition in this study using a webcam to capture an image of the room at any given time who later identified the existing faces. Some of the methods used in the research here is a method of the Dynamic Times Wrapping (DTW), Principal Component Analysis (PCA) and Gabor Wavelet. This system, used in testing with normal facial image expression. The success rate of the introduction with the normal expression of face image using DTW amounting to 80%, 100% and PCA Gabor wavelet 97%.

Aeroponic potato seed production in the lowlands has been carried out by root zone cooling and evaporative cooling in order to reduce high temperature stress for the roots and tops of potato plants. However, the effect of nutrient solution EC on several varieties of potato seeds for an aeroponic system with a combination of root zone cooling and evaporative cooling for potato seed production in the lowlands has not been done. This study aims to obtain the response of potato varieties and the application of different ECs on aeroponic seed production with root zone and evaporative cooling in tropical lowlands. The factors analyzed : 1. Variety (V): V1 (MZ), V2 (Granola K), V3 (Granola L), and 2. Nutrient concentration (EC): EC1 (1.5 mS/cm for Week 1- 4, 2 mS/cm for Week 5 until harvest), and EC2 (1.5 mS/cm for Week 1-4, and 3 mS/cm for Week 5 until harvest), while the design used was RAK with 3 replications. The results showed that the Granola K and EC2 varieties are more efficient for potato seed production in the lowlands with the application of root zone and evaporative cooling. This variety produced the highest number of tubers up to 30 tubers/plant. Similarly, the Granola L and MZ varieties showed similar results with a total number of tubers above 10 tubers/plant. Keywords: Cultivation, Greenhouse, Hydroponics,  Nutrition,  Tubers

The main function of the ampifier is to increase the signal strength, in terms of its voltage or current. In this research, a multistages ac voltage common-emitter amplifer and common-collector amplifier with a single supply of +15 V was designed. The objective is to design an amplifier for amplifying a small ac signal from a transducer. The transducer has an output impedance of 10 k. The amplifier will have a small-signal gain in order of about 1500 and a small-signal bandwith ranging from 100 Hz to 20 kHz. It will drive a load of  300 Ω. The entire circuit consists of a first stage  common-emitter configuration gain amplifier, another second stage common-emitter configuration gain amplifier, and a third stage buffer unity gain common collector amplifier. The three-stages was capacitor coupled. The overall gain of the entire amplifier is the product of the first-stage gain, the second-stage gain, and the third-stage gain. A method called short-circuit time constants was used to determine the apropriate coupling and bypass capacitors. The overall circuit was then simulated by using NI Multisim. The magnitude of the overall gain of the circuit was obtained by performing an interactive analysis and simulation. The frequency response of the amplifier was obtained by performing an AC sweep analyses and simulation. It can be showed that the amplifier’s overall gain obtained from simulation is in agreement with the calculated results. The simulated result for the frequency responses were also in agreement with the requirement

Grumbul Karang Jambe di Kecamatan Tambak Kabupaten Banyumas Provinsi Jawa Tengah yang terletak pada 70 34’ 4.77” lintang Selatan dan 1090 24’ 51.70” bujur Timur dengan ketinggian 200 – 250 Mdpl di kawasan hutan KPH Kedu Selatan.  Oleh karena itu akses jalan masuk belum teraliri listrik PT. PLN. Tujuan dari kegiatan pengabdian ini adalah membuat pembangkit listrik tenaga pikohidro  di daerah tersebut menggunakan generator sinkron magnet permanen untuk mengantisipasi debit air yang rendah pada musim kemarau, sehingga kontinyuitas operasinya dapat diandalkan sebagai sumber penerangan.  Pencapaian tujuan program ini dilakukan dengan metode: 1) pengukuran potensi daya dari aliran sungai, (2) konstruksi generator, (3) konstruksi turbin, (4) pembuatan bendung dan saluran pembawa, (5) instalasi turbin, generator dan penstock di rumah pembangkit, (6) pemanfaatan energi listrik yang dihasilkan oleh pembangkit listrik tenaga piko hidro untuk pengelola. Kegiatan ini telah menghasilkan pembangkit listrik tenaga pikohidro yang mampu mengantisipasi debit rendah pada musim kemarau, 6 titik penerangan yang dapat diekspansi mandiri oleh warga, dan mendapatkan sumber daya manusia yang dapat mengelola pembangkit tersebut.