• Proceedings of the KIEE Conference
• /
• 1999.11c
• /
• pp.597-599
• /
• 1999

Triply encoded HTIS(hadamard transform imaging spectrometer) is a system which applies the grill spectrometer to the HTIS. we consider a nonideality of mask transparent characteristic in estimating spectrum. Triply encoded system increases the SNR(signal to noise ration) by multiplexing effect. In this paper, we suggest an advanced $T^{-1}$ method for spectrum recovery. Then, we proved the superiority of the suggested method by comparing the average MSE(mean square error) of the other recovery methods.

• Journal of Biomedical Engineering Research
• /
• v.16 no.2
• /
• pp.239-248
• /
• 1995

The method of increasing signal to noise ratio (SNR) in a Hadamard transform spectrometer (HTS) is multiplexing. The multiplexing is executed by a mask. Conventional masks are mechanical or electro-optical. A mechanical mask has disadvantages of jamming and misalignment. A stationary electro-optical mask has a disadvantage of information losses caused by spacers which partition mask elements. In this paper, a mixed-concept electro-optical mask (MCEOM) is developed by expanding the length of a spacer to that of lon-off mask element. An MCEOM is operated by stepping a movable mask. 2N measurements are required for N spectrum estimates. The average mean square error (AMSE) using MCEQM is equal to that using a stationary electro-optical mask without spacers for large N. The cost of manufacturing an MCEOM is lower than that of producing a conventional electro-optical mask because an MCEOM needs only (N + 1)/2 on-off mask elements whereas the con¬ventional electro-optical mask needs N on-off mask elements. There are no information losses in the spectrometers having an MCEOM.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.33 no.2
• /
• pp.381-385
• /
• 2004

This study was conducted to develop an HPLC method for determining pantothenic acid in fortified foods which has typically been determined by microbiological assay (MBA) according to AOAC and Korean Food Code approved methods. Pantothenic acid was determined by reversed-phase ion-pair HPLC using UV absorption (200 nm) after extraction with 20 mM potassium phosphate solution by sonication. The recovery of spiked samples and detection limit (LOD) by HPLC were 83.5∼109.6% and 0.5 ppm (mg/kg), respectively. The LOD of the microbiological assay (MBA) was much lower than that of HPLC. The concentrations of pantothenic acid analyzed in all tested samples (n=13) confirmed compliance with declared label claims. The range of recovery ratio by the HPLC method when compared to the microbiological assay was 91.9∼117.6%. There was not significant difference (p<0.01) between the HPLC and MBA methods and the equation of the regression curve was y=1.1428x-0.2269 (r=0.9842). This proposed HPLC method for determining pantothenic acid appears to be suitable for determining pantothenic acid concentrations above 0.25 mg/100 g in fortified foods.