Currently, there is no definitive regulation for the appropriate frequency of data sampling in water distribution networks, yet it plays a crucial role in the efficient operation of these systems. This study proposes a new methodology for determining the optimal frequency of data acquisition in water distribution networks. Based on the decomposition of signals using harmonic series, this methodology has been validated using actual data from water distribution networks. By analyzing 12 types of data collected from two points, it was demonstrated that utilizing the factors and cumulative periodograms of harmonic series enables similar accuracy at lower data acquisition frequencies compared to the original signals.

The purposes of this study were to: a) investigate the percentage distribution and the time spent of dietetic activities and b) estimate dietitian's staffing needs in employee foodservices. In 6 employee foodservices, the dietetic activities were analyzed by work sampling methodology. The results of this study were as follows: 1. The percentage distributions of dietetic activities, delay and non-dietetic activities were 79.06, 20.39, and 1.55%, respectively; 2. The major activities of dietitians in employee foodservice were production management 21.00%, purchasing management 16.73%, record keepig 14.40%, and menu management 6.30%, 3. The total labor time per week was 3,310 min (55.16 hr) and specially the time spent on 13 dietetic activities was 2,626 min (43.77 hr). 4. The time spent per week on major activities of dietitians such as production management, purchasing management record keeping, and menu management were 693.93, 554.83, 483.99, and 205.22 min, respectively.