The authentication, identification, and copyright protection can be obtained by constructing the digital image watermarking technique. Watermark robustness and imperceptibility account for the capability of the hidden watermark to survive the manipulation. The proposed paper is a robust algorithm for digital image watermarking with 3-level discrete wavelet transform (DWT) with some attacks method. The 3-level DWT method was used constants α=0.01 and 0.03 as a function of how depth the watermark inserts to the host image in the insertion and extraction process. The algorithm was evaluated using 8 bits per pixel (bpp) grayscale, 1024x1024 pixels for the host image, and 256x256 pixels for the watermark image. The method is also implemented some experimental with attacks such as gaussian, salt and pepper, blurring, and compression. The algorithm is relatively acceptable of good quality, achieves low-value mean squared error (MSE), high peak signals to noise ratio (PSNR), and structural similarity index metric (SSIM) value approach to 1. It is found that the highest image quality measurements by using α=0.03 with the attacking method of salt and pepper yield MSE=0.01, PSNR=45.6 dB and SSIM=0.95, respectively.

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Activities such as planting and gardening become one of prominent hobbies. An issue of having such well grown plants is the impractical and unachieavable task to monitor 24 hours a day, thus we need a smart gardening system that can monitor the garden on demand. One of the problems in residential gardening systems is how to water the plants while the owner is not at home. Some of people have an adequate knowledge of using IoT to make their life easier. This paper proposes a simple automatic gardening system in watering several plants as programmed. In addition, this system allows human’s manual intervention either locally or remotely via Internet, to control a water pump. To build this smart gardening system, we use Xiaomi home application from Google Play. In this application, we can set the program to water the plants daily with definite time periodic independently.

ABSTRAKSistem komunikasi suara bawah air telah dikenal sejak lama, diantaranya sonar dan akustik. Seiring perkembangan zaman dan kemajuan teknologi, kini hadir komunikasi dengan media transmisi cahaya tampak yaitu Visible Light Communication (VLC) yang dapat diterapkan pada komunikasi bawah air. Pada penelitian ini telah dilakukan komunikasi suara bawah air (simplex) menggunakan VLC, dengan media akuarium berisi air dan beberapa pengujian diantaranya menggunakan color filter, didapat hasil pengujian terbaik yaitu tegangan 4,4 Vpp dan frekuensi 3,003 kHz untuk color filter yellow, pengujian menggunakan lensa didapat hasil pengujian terbaik yaitu tegangan 4,4 Vp-p dan frekuensi 3,051 kHz untuk lensa (+50), dan pengujian terakhir menggunakan lampu UV didapat hasil pengujian terbaik dengan tegangan 4,4 Vp-p dan frekuensi 3,010 kHz. Implementasi sistem VLC ini menunjukkan hasil yang baik dan layak untuk diterapkan pada komunikasi suara bawah air (simplex).Kata kunci: VLC, Komunikasi Suara Bawah Air, Simplex. ABSTRACTUnderwater voice communication systems have been known for a long time, including sonar and acoustics. Along with the development and advancement of technology, now there is communication with visible light transmission media, namely Visible Light Communication (VLC) which can be applied to underwater communication. Under this study underwater voice communication (simplex) has been carried out using VLC, with aquarium media containing water and several tests including using a color filter, the best test results obtained are voltage 4.4 Vp-p and frequency 3.003 kHz for yellow color filter, testing using the lens obtained the best test results namely voltage 4.4 Vp-p and frequency 3.051 kHz for lenses (+50), and the last test using UV lights obtained the best test results with a voltage of 4.4 Vp-p and a frequency of 3.010 kHz. The implementation of the VLC system shows good and feasible results to be applied to underwater voice communication (simplex).Keywords: VLC, Underwater Voice Communication, Simplex.

ABSTRAKSaat ini, cahaya tampak dimanfaatkan oleh manusia hanya sebagai penerangan saja. Akan tetapi, beberapa penelitian telah membuktikan bahwa cahaya tampak dapat dimanfaatkan pula pada sistem komunikasi, yang dinamakan Visible Light Communication (VLC). Pada penelitian ini, sebuah metoda menggunakan color filter diidentifikasi dalam mengimplementasikan sistem bidirectional pada teknologi VLC. Dengan adanya penelitian ini, sebuah sistem bidirectional Visible Light Communication (Bi-VLC) dapat diimplementasikan dengan menggunakan color filter tertentu yang dipasangkan pada posisi uplink dan downlink. Sinyal informasi berupa sinyal audio ditansmisikan melalui VLC transmitter (Tx) yang dipasang color filter dan diterima oleh color filter pada VLC receiver (Rx) setelah melalui media cahaya. Pengujian menunjukan bahwa sistem telah dapat melewatkan sinyal pada frekuensi audio dengan jarak maksimum dari sistem adalah 2,3 m. Sedangkan pasangan color filter yang memiliki kinerja paling baik untuk BI-VLC adalah Azure (Tx) dengan Charteuse Green (Rx), Charteuse Green (Tx) dengan Charteuse Green (Rx), dan Rose (Tx) dengan Charteuse Green (Rx).Kata kunci: Bidirectional, Visible Light Communication (VLC), Color Filter, Audio ABSTRACT Currently, visible light are utilized by humans as illumination only. However, several research have proven that visible light can also be used in communication systems, called Visible Light Communication (VLC). In this research, a method of using color filters was identified for bidirectional systems on VLC technology. With this research, a bidirectional Visible Light Communication (Bi-VLC) system can be implemented using a specific color filter paired in uplink and downlink mode. The audio signal as information is transmitted through a VLC transmitter (Tx) installed by a color filter and received by the color filter on the VLC receiver (Rx) after going through the light media. The result shows that the system has been able to pass the signal at the audio frequency with the maximum distance of the system is 2.3 m. While the best performance of color filter pair for BI-VLC is Azure (Tx) with Charteuse Green (Rx), Charteuse Green (Tx) with Charteuse Green (Rx), and Rose (Tx) with Charteuse Green (Rx).