Accuracy of Broiler Activity Index as Affected by Sampling Time Interval

Different time intervals between consecutive images have been used to determine broiler activity index (AI). However, the accuracy of broiler AI as affected by sampling time interval remains to be explored. The objective of this study was to investigate the effect of the sampling time interval (0.04, 0.2, 1, 10, 60, and 300 s) on the accuracy of broiler AI at different bird ages (1–7 weeks), locations (feeder, drinker, and open areas) and times of day (06:00–07:00 h, 12:00–13:00 h, and 18:00–19:00 h). A ceiling-mounted camera was used to capture top-view videos for broiler AI calculations. The results show that the sampling time interval of 0.04 s yielded the highest broiler AI because more bird motion details were captured at this short time interval. The broiler AIs at longer time intervals were 1–99% of that determined at the 0.04-s interval. The broiler AI at 0.2-s interval showed an acceptable accuracy with 80% less computational resources. Broiler AI decreased as birds aged but increased after week 4 at the drinker area. Broiler AI was the highest at the open area for weeks 1–4 and at the feeder and drinker areas for weeks 5–7. It is concluded that the accuracy of broiler AI was significantly affected by sampling time intervals. Broiler AI in commercial housing showed both temporal and spatial variations.

Application of Multistep Inversion Method for Online Monitoring Aerosol Particle Size Distribution and Aerosol Concentration

Aerosol concentration in the flow is usually time varying, and aerosol particle size distribution (PSD) is considered to be unchanged, which increases the difficulty of the measurement of aerosol PSD and concentration online. To solve these problems, a kind of multistep inversion method based on the angular light-scattering (ALS) signals is proposed. First, the aerosol PSD is estimated using shuffled frog-leaping algorithms (SFLAs) from relative ALS signals. Then, with aerosol PSD as priori information, the aerosol concentration is obtained by the Kalman filter (KF) algorithm, widely used in the real-time control system of industrial facilities for its ability of fast predictions. The result reveals that the performance of the improved SFLA is better than that of the original SFLA in solving the aerosol PSD. Moreover, in studying the aerosol concentration, more accurate results can be obtained with larger standard deviation of process noise or smaller standard deviation of measurement noise, while decreasing sampling time interval can improve the accuracy of retrieval results and reduce time delay to a certain degree. So, to improve retrieval accuracy, the noise should be controlled, and appropriate sampling time interval should be selected. All the numerical simulations confirm that the methodology provides effective and reliable results in real-time estimating.

STUDI DINAMIKA SENYAWA FOSFAT DALAM KUALITAS AIR SUNGAI CILIWUNG HULU KOTA BOGOR

Study of Dynamics of Phosphate in the Water Quality in Bogor of Upstream Ciliwung RiverCiliwung River has existed and become an important part of the community since ancient period. Since 2009, the Ciliwung River has been polluted condition from upstream. One of the pollutant that could decrease the quality of river water was phosphate. Excessive phosphate level in water bodies caused nutrient enrichment conditions (eutrophication). The presence of nitrate supporting phosphate also caused algae blooming, one of the environmental problem. The research was conducted to determine the dynamics of the phosphate compound of Ciliwung River whether the pollution was reduced, same, or worse. The research included sampling of river water at three points of Katulampa, Pasar Bogor, and Warung Jambu River with sampling time interval of 8 hours in a day for 3 weeks in a row. The data of phosphate and nitrate concentration were measured and compared to the results in PP No.82 year 2001. The total of phosphate in Ciliwung river water has exceeded threshold level in accordance with the environmental quality standard of PP. 82 year 2001, and has been indicated to be in eutrophication condition.Keywords: Ciliwung River, Water Quality, Water Pollution, Phosphate.ABSTRAKSungai Ciliwung telah ada dan menjadi bagian penting masyarakat sejak zaman purba. Namun seiring dengan berlalunya waktu dan perkembangan pesat, sejak tahun 2009 Sungai Ciliwung telah tercemar dari hulu. Salah satu polutan yang bisa menurunkan kualitas air sungai adalah fosfat. Keberadaan fosfat yang berlebihan di badan air dapat menyebabkan kondisi pengayaan nutrisi (eutrofikasi), dan dengan dukungan nitrat dapat menyebabkan algae blooming yang menjadi salah satu masalah lingkungan. Penelitian ini dilakukan untuk mengetahui dinamika senyawa fosfat Sungai Ciliwung apakah pencemarannya berkurang, sama, atau lebih buruk. Ruang lingkup penelitian meliputi pengambilan sampel air sungai pada tiga titik Katulampa, Pasar Bogor, dan Warung Jambu dengan interval waktu sampling 8 jam dalam sehari, dan dilakukan setiap minggu selama 3 minggu berturut-turut. Kemudian dilakukan analisis sampel di laboratorium, serta interpretasi data dengan membandingkan hasilnya terhadap PP No.82 tahun 2001. Nilai total fosfat di air sungai Ciliwung Hulu tidak memenuhi standar kualitas lingkungan PP. 82 tahun 2001, dan diindikasikan berada dalam kondisi eutrofikasi.Kata kunci: Sungai Ciliwung, Kualitas Air, Polusi Air, Fosfat.

Time-Expanded Sampling for Ensemble Kalman Filter: Assimilation Experiments with Simulated Radar Observations

A time-expanded sampling approach is proposed for the ensemble Kalman filter (EnKF). This approach samples a series of perturbed state vectors from each prediction run not only at the analysis time (as the conventional approach does) but also at other time levels in the vicinity of the analysis time. Since all the sampled state vectors are used to construct the ensemble, the number of required prediction runs can be much smaller than the ensemble size and this can reduce the computational cost. Since the sampling time interval can be adjusted to optimize the ensemble spread and enrich the ensemble structures, the proposed approach can improve the EnKF performance even though the number of prediction runs is greatly reduced. The potential merits of the time-expanded sampling approach are demonstrated by assimilation experiments with simulated radar observations for a supercell storm case.

Encoder-Less Synchronized Averaging Using Order Tracking and Interpolation

Synchronized averaging is a very useful signal processing technique, in particular, for condition monitoring of rotating machinery. It enhances the signal to noise ratio by attenuating noises that are not repeated from one rotation to the next. Its use, however, is limited due to the costly hardware needed to trigger the sampling at exactly the same angular positions rotation after rotation. This paper describes an improved order tracking technique which employs a Kalman filter to track the instantaneous rotating speed of machinery and an interpolation technique to resample data obtained under constant sampling time interval into data sampled at constant angular increments. Experiments were conducted to validate the proposed algorithm. Comparing the synchronized average obtained by the order tracking algorithm with the true average using encoder triggering, no significant difference can be seen until 3x of meshing frequency. Since the technique only requires band-pass filtered vibration and a once-per-revolution index signal, it is much simpler compared to the existing technique which requires complex and cumbersome hardware to track the rotating speed.