• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6A
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• pp.871-880
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• 1999

In this paper, a pseudo-noise(PN) tracking and demodulation circuits are analyzed and designed for a direct-sequence/spread-spectrum multiple access system under a mobile fading channel. We consider noncoherent delay locked loop(DLL) as a PN code tracking loop which has 1/8 PN chip resolution. The tracking performance of DLL is evaluated in terms of locking time from a loose state and tracking jitter. The received signal is demodulated to original data by despreading with PN code locked by DLL. Also the designed circuit supports sound service of 32Kbps and in-band signal with 4.096MHz chip clock. The circuits are implemented and verified with FPGA, which is shown completely data recovery under AWGN 7dB and will be available for IMT-2000.

• Food Science of Animal Resources
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• v.32 no.4
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• pp.428-433
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• 2012

The objective of this study was to identify appropriate aging conditions, changes in nucleotide-related compounds, chemical changes, and a sensory evaluation of duck meat during aging at $0^{\circ}C$ for 7 d. Twenty one 45-day-old Pekin white ducks samples were separated into breast and leg meat. ATP was not detected for almost the entire aging period because ATP was depleted immediately after slaughter. Inosine monophosphate (IMP) was highest on day 1 ($26.69{\mu}mol/g$), and then it rapidly decreased to $7.11{\mu}mol/g$ on day 7. However, this level was not different between breast and leg meat. Hypoxanthine (Hx) content of breast meat was $14.88{\mu}mol/g$, whereas that of leg meat was $16.41{\mu}mol/g$. Inosine content of breast meat was double than that of leg meat. The pH values of breast and leg meat were 5.90-6.05 and 6.23-6.73, respectively, during the aging period. Volatile basic nitrogen content of breast and leg meat increased during aging. Breast meat had good sensory evaluation scores for flavor (7.4), juiciness (6.8), tenderness (7.2), and overall acceptance (7.4) on day 3. Similar to breast meat, leg meat also had good sensory evaluation scores. Therefore, it is concluded that the appropriate aging period is 3 d for duck breast meat and 1 day for leg meat at $0^{\circ}C$.

• Animal Bioscience
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• v.37 no.7
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• pp.1277-1288
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• 2024

Objective: This study was aimed to investigate the effect of fresh and dried hydrolyzed Cordyceps militaris (CM) mushroom with proteolytic enzymes; bromelain (CMB), flavorzyme (CMF), and mixture of bromelain: flavorzyme (CMBF) on quality properties of spent hen chicken. Methods: Mushroom extract (CME) were combined with three proteolytic enzyme mixtures that had different peptidase activities; stem bromelain (CMB), flavorzyme (CMF), and mixture of stem bromelain:flavorzyme (CMBF) at (1:1). The effect of these hydrolysates was investigated on spent hen breast meat via dipping marination. Results: Hydrolyzation positively alters functional properties of CM protease. in which bromelain hydrolyzed group (CMB) displayed the highest proteolytic activity at 4.57 unit/mL. The antioxidant activity had a significant increment from 5.32% in CME to 61.79% in CMB. A significantly higher emulsion stability index and emulsification activity index compared to CME were another result from hydrolyzation (p<0.05). Texture properties along with the shear force value and myofibrillar fragmentation index were notably improved under CMB and CMBF in fresh condition. Marination with CM mushroom protease that was previously hydrolyzed with enzymes was proven to also increase the nucleotide compounds, indicated by higher adenosine 5'-monophosphate (AMP) and inosine 5'-monophosphate (IMP) in hydrolysate groups (p<0.05). The concentration of both total and insoluble collagen remained unchanged, meaning less effect from CM protease. Conclusion: This study suggested the hydrolyzation of CM protease with bromelain or a mixture of bromelain:flavourzyme to significantly improve functional properties of protease and escalate the taste-related nucleotide compounds and texture profiles from spent hen breast meat.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.2
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• pp.267-273
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• 2010

The objective of this study was about physicochemical characteristic of puffer muscle and skin to promote the utilization of puffer as fish protein. In proximate composition, crude protein of dried puffer muscle and skin powders were 89.5% and 82.7%, respectively. Skin powders had higher lipid contents than muscle powders. Ash contents of muscle powders were higher than those of skin powders. In nucleotides and their related compounds, the contents of nucleotides were in order of IMP and ADP. The contents of saturated fatty acid in puffer muscle (83.9%) was higher than skin powders (66.3%). Oleic acid, mono-unsaturated fatty acid, in skin powder (25.9%) was higher than in muscle powders. Seventeen kinds of composition amino acids were detected in muscle powders, while 16 kinds of amino acids were found in skin powders. Total contents of amino acid in muscle powders (83,739 mg/100 g) were higher than those of skin powders (75,361 mg/100 g). In the muscle powders of puffer, glutamic acid was the highest amino acid with the concentration of 13,707 mg/100 g, and was in order of aspartic acid, lysine, leucine, arginine, alanine, valine and glycine. In skin powders, glutamic acid was the highest content with 14,843 mg/100 g followed by proline, alanine and arginine. Twenty five kinds of free amino acids were detected in dried muscle powders, while 22 kinds of free amino acids were found in dried skin powders. Taurine of dried puffer muscle and skin powders was the highest free amino acid with the concentration of 554.4 mg/100 g and 153.6 mg/100 g, respectively. The contents of total free amino acids of dried muscle powders were higher than those of dried skin powders. Especially, cysteine was only detected in dried muscle with the content of $159.3\pm1.8$ mg/100 g.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.4
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• pp.312-320
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• 1986

The taste compounds in low salted and fermented damsel fish, Chromis notatus, substitute lactic acid, sorbitol and ethyl alcohol for sodium chloride and fatty acid composition were analysed during fermentation. The best organoleptic result was obtained after 60 days fermentation. Volatile basic nitrogen (VBN) was increased significantly until 10 days fermentation period but low salted and fermented products ($8\%\;and\;10\%$ salted) gave lower VBN value than that of $20\%$ salted after 85 days fermentation. Amino nitrogen also increased rapidly after 10 days fermentation and slowed down up to 60 days but it was decreased after 85 days. The abundant amino acids in raw damsel fish were lysine, taurine, aspartic acid, glutamic acid, proline and alanine and those were consisted of $58.8\%$ of the total free amino acids but arginine and tyrosine were trace in content. After 60 days fermentation, lysine, glutamic acid, alanine, leucine, aspartic acid and valine were dominant which marked $58{\sim}71\%$ of the total free amino acids but taurine was not detected. In raw ingredients, IMP was abundant which marked $18.6{\mu}mole/g$ while in fermented sample, hypoxanthine was predominant but ATP and ADP were not detected. During fermentation TMA was increased but TMAO was decreased which marked only trace after 60 days. Total creatinine was rapidly increased after 10 days but notable change was not showed after 60 days fermentation. The major fatty acids of total lipid in raw and fermented damsel fish were 16:0, 18:1, 16:1, 22:6 and 20:5 in order.

• Journal of Aquaculture
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• v.5 no.1
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• pp.69-79
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• 1992

The muscle extracts of the ascidian, Halocynthia roretzi cultured for two and three years old on the southern coast near Chungmu and the eastern coast near Pohang of Korea, were analyzed for extractive nitrogen (EN), free amino acids (FAA), combined amino acids (CAA), nucleotides and related compounds (NRC), quaternary ammonium bases and guanidino compounds using specimens collected in February 1989 and in April 1989, and compared for those contents with each other. As for the amount of EN, no remarkable difference was found between two- and three-year-old samples collected at St. 1 in the spring and winter seasons, while at St. 2 in the spring season the two-year-old sample was distinctly lower than the three-year-old one. Taurine, proline, glutamic acid, glycine and alanine were the major FAA in every sample. The amount of taurine, the most prominent FAA, was higher in three-year-old sample than in two-year-old one regardless of sampling station and season. Most of the other major FAA showed a similar tendency to EN at both sampling stations in both seasons. Adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP), adenosine 5'-monophosphate (AMP), inosine 5'-monophosphate (IMP), inosine (Ino) and hypoxanthine (Hyp) were detected in all the samples and ATP, ADP and AMP were the major ingredients. The amounts of total NRC were in parallel with those of EN and total FAA. As for the contents of betaines, two- and three-year-old samples collected in the winter season exhibited a great discrepancy each other, the former being clearly lower than the latter, but no remarkable difference was observed between two samples of two groups in the spring season. In proximate composition of the muscles, the two-year-old sample was considerably higher in moisture content and lower in protein and glycogen contents than the three-year-old one at St. 2 in the spring season. The large discrepancies observed between two- and three-year-old samples from St. 2 seems to be attributable to the difference in size of samples rather than to the difference in age.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.4
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• pp.615-643
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• 1998

The purpose of this study was to evaluate the effect of cantilever length, load, and implant number on the stress distribution of implant supported fixed prosthesis. In the replica of an edentulous human mandible, four or five implants were placed and spaced evenly between the mental foramina and symmetrical gold alloy cast superstructures with cantilever were fabricated. Strain gauges were placed in buccal and lingual side of implants. 9, 15, 21kg of loads at varying cantilever lengths were applied to the occlusal surface of fixed prostheses. The strains were recorded from each gauge and principal stresses were calculated The results were as follows : 1. Increasing the length of the cantilever increased the stresses on the bone supporting implants. and the ratio of increase became high as increasing the load. 2. In the model with four implants, the highest compressive stress was measured on lingual side of the first implants nearest loading point and the highest tensile stress was measured on buccal side of the second implants. 3. In the model with five implants, the highest compressive stress was measured on lingual side of the first implants nearest loading point. And the highest tensile stress was measured on buccal side of the second implants, and lingual side of the third implants. 4. There was no significant change of the magnitude of stress on the most distal imp]ant of non cantilevered side as increasing the cantilever length or load. 5. In general, the superstructure supported by five implants reduced the stress and was less affected by cantilever length compared to the support provided by four implants.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.2
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• pp.325-330
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• 1996

전남지방의 전통 수산발효식품인 토하젓의 인지도 향상 및 국가경쟁력을 갖춘 지역특산품으로 발전시키기 위한 일련의 연구로써, 식품학적 기초자료를 얻기위하여 숙성기간이 다른 시판 토하젓을 구입하여 정미성분을 분석.검토하였다. 저온(5$\pm$2$^{\circ}C$)에서 90일간숙성시킨 토하젓의 전체 유리아미노산 함량은 건물당 1873.0mg/100g)보다 2배이상 많았다. 한편 숙성된 토하젓의 주요 유리아미노산(719.4mg/100g) 보다 2배 이상 많았다. 한편 숙성된 토하젓의 주요 유리아미노산은 glutamic acid, alanine, leucine, valine 및 phenylalanine으로 전체 유리아미노산에 대해 58.6%를 차지하였다. 핵산 관련물질은 담금 직후 및 숙성된 토하젓 모두 hypoxanthine의 함량이 월등히 많았으며, 그 다음으로 AMP 및 IMP순이였다. 그리고 숙성된 토하젓은 담금 직후의 토하젓과 비교해서 AMP 및 IMP는 적었으나, hypoxanthine의 함량은 많았다. 불휘발성 유기산을 GC분석한 결과, 담금 직후 및 숙성된 제품 모두에 lactic acid가 가장 많아 각각 건물당 389.3mg/100g 및 752.3mg/100g이였고, succinic acid는 미량 함유되어 있었다. 90일간 숙성된 TMAO, betaine 및 total creatinine 함량은 건물량 기준으로 각각 63.6mg/100g, 179.1mg/100g 및 123.7mg/100g이었다. Omission test를 이용하여 각정미성분을 관능검사한 결과, 유리아미노산 및 불휘발성 유기산이 토하젓의 맛에 중요한 역할을 하는 것으로 밝혀졌으며, 핵산 관련물질은 그다지 맛에 대한 기여도가 높지 않았다. 따라서 시판 토하젓의 맛에는 유리 아미노산 및 불휘발성 유기산이 중요한 역할을 하며, 핵산 관련물질이나 TMAO, betaine 및 total creatinine은 보조적인 역할을 할 것으로 생각된다.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.3
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• pp.569-583
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• 1995

Disinfection of dental impressions are necessary due to contamination with patient’s saliva and blood, which is a potential for cross-infection. The purpose of this study was to evaluate the effects of disinfection of four hydrophilic rubber impression materials with three disinfecting solutions, on the dimensional stability and surface hardness of improved stone casts. Three hydrophilic vinyl polysiloxane impression materials(Express, Reprosil, Exafine) and one polyether impression material(Impregum-F) were mixed according to the manufacturer’s directions and impressions were made on a ADA specification No. 19 stainless-steeldie. On removal of the impressions, each impression was immersed in one of the disinfectants(Banicide, Potadine, Clorox) for 10 minutes. After disinfection, type IV improved stone. casts were poured. On this cast, the linear dimension and surface hardness were measuredusing a Measurescope(Nikon, Japan) and a Barcol hardness tester(Barber, Colman Co U. S. A). The results were as follows : 1. The improved stone casts from disinfected Reprosil and Impregum-F impression material did not show dimensional changes(P>0.01). Those from disinfected Express and Exafine impression material showed dimensional changes(P<0.01). The amount of shrinkage was not clinically significant. 2. The improved stone casts from disinfected Express impression material did not exhibit changes in surface hardness(P>0.01), but those from disinfected Reprosil, Exafine, Imp regnum-F impression material showed changes in surface hardness(P<0.01). 3. The dimensinal stability and surface hardness of the improved stone casts were satisfactory using Banicide on Express, all disinfectants used in this study on Reprosil, Potadin and Clorox on Exafine, Banicide and Clorox on Impregum-F. According to these results, immersion disinfection of hydrophilic rubber impression mate rials did not adversely affect the resultant casts. Nevertheless compatibility tests of impression materials and disinfectants should be done when disinfecting impressions.

• School Mathematics
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• v.5 no.1
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• pp.27-42
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• 2003

The current 7th National Mathematics Curriculum had been developed as a learner-centered curriculum and begun to apply to high school since 2002. This paper discusses issues related to the high school mathematics curriculum application into high school. The mathematics curriculum for grades 11 and 12 was developed primarily as a learner-centered one to provide five elective courses according to the needs of students based on their future occupation and attitudes. Discussion starts with the differences of the five elective courses: the three of them have dependent and sequential structure and the two are totally different with regards to their levels of difficulty and the content they span. It is claimed that the frameworks of the 2005 National Ability Test for the College Entrance and the minimal enrollment requirements of several influential colleges' admission policy make the high school mathematics education very rigid, unflexible, and anti-educational. Several suggestions to recover and imp-rove the high school mathematics education and the spirit of the 7th curriculum are presented.