New Reconstruction Method for Needle Contrast Optimization in B-Mode Ultrasound Image by Extracting RF Signal Parameters in Frequency Domain

Ultrasound-guided needle insertion has become standard in medical interventional procedures. Regardless of its advantages, it still has crucial problems related to needle visibility. Some technical factors affect the visibility with non-linear characteristic, i.e. frequency, insertion angle and depth. Here, backscattered signal parameters from measurement were compared to a simulation of a resonance scattering model. Raw radio frequency (RF) data were reconstructed with a new method to represent unique information on total backpropagation from the needle, which consists of non-resonance and resonance scattering components. The result suggests that reconstruction of the needle in B-mode images should be derived from the maximum power spectral density and the energy spectral density to optimize the contrast of the needle. In measurements with the center frequency at 1.87 MHz, the effect of resonance scattering on the total backpropagation around critical angles could be observed more clearly with this method than with standard reconstruction based on the signal envelope. The simulation showed that the fractional bandwidth of the spectrum of the backscattered pressure field centered at 1.87 MHz was relatively optimal at 40% to 100%. So that the simulation of the resonance scattering model can be used to predict the backscattered response from the needle, it must be able to confirm it to the real conditions of RF data with random characteristics. Therefore, extraction of the backscattered pressure field in a simulation with fractional bandwidth should be a concern

Prototipe Alat Kontrol Derajat Keasaman dan Konduktivitas Listrik Selama Masa Tanam pada Larutan Nutrisi Hidroponik Tanaman Cabai (Capsicum frutescens L.)

Metode hidroponik bukan hal yang baru di kalangan petani khususnya di wilayah yang kurang lahan untuk bercocok tanam. Salah satu metode hidroponik yang sering digunakan yaitu metode Nutrient Film Technique karena mudah dikembangkan dan digunakan terutama di wilayah yang kurang lahan untuk bercocok tanam. Akan tetapi tanaman hidroponik sangat bergantung pada larutan nutrisi dan harus sesuai kebutuhan tanaman. Pada penelitian ini akan dibuat sistem otomatis untuk proses pencampuran larutan nutrisi pada tanaman cabai menggunakan sensor EC dan pH untuk mendeteksi nilai konduktivitas listrik (EC) dan derajat keasaman (pH) nutrisi selama masa tanam. Pada penelitian ini menggunakan metode penelitian eksperimen, untuk mengetahui pengaruh variabel independen terhadap variabel dependen dalam kondisi yang terkendalikan. Dari hasil kalibrasi sensor didapatkan nilai rerata eror pada sensor pH sebesar 10,77% dan sensor EC sebesar 5,46%. Sementara, pengambilan data pengujian prototipe dilakukan pada menit ke 15, 30, 45 dan 60. Hasil pengontrolan EC pada waktu tersebut secara berturut-turut sebesar 1324,90 µS/cm; 1369,63 µS/cm; 1347,74 µS/cm dan 1325,26 µS/cm. Sedangkan, hasil pengontrolan pH pada rentang waktu tersebut secara berturut-turut sebesar 6,23; 5,90; 5,78 dan 6,17. Hasil yang didapatkan pada penelitian ini memiliki prospek untuk dikembangkan lebih lanjut untuk merumuskan jenis teknologi pengiriman data pengukuran EC dan pH yang tepat dari prototipe kepada pengguna secara kontinu

Using Electroencephalogram (EEG) to Understand The Effect of Price Perception on Consumer Preference

Abstract. The research examines the influence of price as product cues on consumer’s perception and evaluation by using the application of electroencephalogram (EEG). This method can give objective information about consumer reactions towards product cues that will drive consumer’s choice. The main research objective was to observe and evaluate consumer’s brain activity in different brain regions while they were being exposed by several price levels (low, medium, high) of underwear as stimuli and focused mainly on liking/disliking the stimuli. The participants consist of 10 female and 10 male consumers within 18-24 years old, have normal vision, right handed, and considered as potential purchasers of underwear. The participant’s brain activity was collected using Emotiv EPOC neuroheadset (EEG) with international 10/20 system and was obtained in Beta frequency bands (13–30 Hz). The result indicated that there was a clear and significant change (p<0.05) in the EEG brain spectral activities of right and left hemisphere in the frontal (F3 & F4), temporal (T7 & T8), and parietal (P7 & P8) regions when participants indicated their attentiveness towards each price level stimulus. The results show, the male and female participant’s tactile sensations in parietal lobe does not give more favorable attention towards particular price stimulus, but the difference price perceptions in parietal lobe can lead to rational preference and give most favored response towards high price stimulus. Analyzing of price perception may help to understand the differences in price-related emotions and preference, which can gain insights into an alternative pricing strategy that can lead to influence consumers buying decision.Keywords:  EEG, Price, Perception, Preference, Underwear

New Hermitian self-dual MDS or near-MDS codes over finite fields

A linear code over a finite field is called Hermitian self-dual if the code is self-dual under the Hermitian inner-product. The Hermitian self-dual code is called MDS or near-MDS if the code attains or almost attains the Singleton bound. In this paper we construct new Hermitian self-dual MDS or near-MDS codes over and of length up to 14

Prototipe Pengontrolan Kepekatan Larutan Nutrisi pada Tanaman Tomat (Solanum Lycopersicum) Berbasis Jaringan Sensor Nirkabel

Pengontrol kepekatan larutan nutrisi adalah alat yang digunakan untuk mengkondisikan kepekatan larutan nutrisi agar tetap berada pada set point ruang lingkup pertanian. Pengontrol kepekatan larutan nutrisi digunakan pada sistem hidroponik khususnya metode Nutrient Film Technique (NFT). Dalam hal ini pengontrolan dilakukan pada kepekatan nutrisi pada reservoir yang digunakan sebagai media air yang sudah tercampur dengan nutrisi yang kemudian dialirkan pada tumbuhan. Di masa depan, alat ini diharapkan bisa membantu petani hidroponik agar dapat melakukan pengontrolan secara otomatis sehingga mampu untuk memperkecil peluang terjadinya gagal panen. Pengontrolan ini dilakukan dengan menggunakan sensor TDS (Total Dissolved Solid) yang digunakan untuk mengukur kepekatan suatu larutan. Dalam penelitian ini, pengontrolan kepekatan larutan nutrisi difokuskan untuk kebutuhan nutrisi tanaman tomat. Dari hasil uji kalibrasi yang dilakukan pada tiga titik uji pengukuran 96,2 ppm, 500 ppm, dan 1000 ppm besar nilai kesalahan secara berturut turut adalah 10%, 7%, dan 4%. Ketika prototipe sudah dipasang pada instalasi hidroponik NFT untuk menambah kepekatan sebesar 180 ppm perbandingan antara larutan nutrisi dengan reservoir campuran adalah 1 : 200. Pada pengujian debit pompa, besar debit pompa yang sudah dipasang 3,33 mL/s. Kemudian, ketika dilakukan pengujian pengontrolan dari jarak jauh dapat dipastikan bahwa penunjukkan kepekatan nutrisi dari jarak 0 km sama 8,1 km adalah sama

Segmentasi Citra Secara Semi-otomatis Untuk Visualisasi Volumetrik Citra Ct-scan Pelvis

Semi-Automatic Image Segmentation for Volumetric Visualization of Pelvis CT Scan-Images. The currentdevelopment of computerized tomography (CT) has enable us to obtain cross sectional image using multi slicingtechniques in an order of few seconds. The obtained images represent several tissue structures on cross section slicebeing imaged. One challenge to help diagnosis using CT images is extracting an anatomic structure of interest using amethod of image segmentation and volumetric visualization with the assistance of computers. In case of volumetricvisualization of pelvis bones extracted from multi-slice CT images, whole images which are containing part of pelvisbone structures must be segmented. In this research, an image segmentation technique based on active contour isimplemented for semi-automatic multi slice image segmentation. Image segmentation steps are initialized with a definemodel of 2D curve on the first slice image manually. Next, its model curve is deformed to reach the final result of 2Dcurve that fits to boundary edges of pelvis bone image. The final result of 2D curve on previous slice image was used asan initialization model of 2D curve on the next slice images. This process will continue until the final slice image. Thissegmentation method was compared with the segmentation method based on threshold from homogenous intensitydistribution and manual segmentation method. Quantitative analysis from the results of segmentation on each slice andqualitative analysis on the representation of volumetric visualization are performed in this research