• Fisheries and Aquatic Sciences
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• v.25 no.3
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• pp.140-150
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• 2022

A method of ultrahigh performance liquid chromatography coupled to high resolution mass spectrometry (UPLC-HRMS) was established for characterization of the lipid profile of Skipjack tuna. Over 300 lipid molecular species were identified through cross-acquisition in both positive and negative ion mode. Phospholipids (PLs) were dominant in Skipjack tuna. Lysophosphatidylethanolamine (LPE), phosphatidylethanolamine (PE), lysophosphatidylcholine (LPC) and phosphatidylcholine (PC) were the main lipid molecular species in PLs, accounting for 89.24% of the total PLs. The ratio of sphingolipids (SLs) and glycerolipids (GLs) were considerable, accounting for 12.30% and 13.60% of the total lipids respectively. Ceramide (Cer) was the main lipid molecular species of SLs, accounting for 64.96% of total SLs, followed by sphingomyelin (SM), accounting for 25.45% of total SLs. Ether diglycerides (ether DG) were the main lipid molecular species of GLs (97.83%). The main fatty acids (FAs) are unsaturated fatty acids (UFAs) in Skipjack tuna. Besides, a new FAs class branched fatty acid esters of hydroxy fatty acids (FAHFA) was detected, together with the FA. The active lipids identified in this study can be used to evaluate the nutritional value of Skipjack tuna.

• Korean Journal of Clinical Laboratory Science
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• v.56 no.1
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• pp.85-88
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• 2024

Electroencephalography (EEG) is a test that diagnoses epilepsy and measures brain function. During EEG, the space between the electrode and the skin is filled with a conductive paste to reduce the impedance between the electrode and the scalp, which helps measure the EEG signals. This study compared the artifacts of the two representative conductive pastes (Ten20 and Elefix). The artifacts, noise, and satisfaction were surveyed after using the two conductive pastes. The two conductive pastes had similar artifacts and noise, but the survey results showed that the Elefix conductive paste had better satisfaction and adhesion. This result may be explained by the imprinting effect according to the experience of using the Elefix conductive paste first in the EEG class. Hence, further research is needed.

• Journal of KIISE:Software and Applications
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• v.28 no.2
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• pp.192-200
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• 2001

본 논문은 조명 변화, 표정 변화, 부분적인 오클루전이 있는 얼굴 영상에 강인하고 적은 메모리양과 계산량을 갖는 효율적인 얼굴 인식 방법을 제안한다. SKKUface(Sungkyunkwan University face)라 명명한 이 방법은 먼저 훈련 영상에 PCA(principal component analysis)를 적용하여 차원을 줄일 때 구해지는 특징 벡터 공간에서 조명 변화, 얼굴 표정 변화 등에 해당되는 공간이 최대한 제외된 새로운 특징 벡터 공간을 생성한다. 이러한 특징 벡터 공간은 얼굴의 고유특징만을 주로 포함하는 벡터 공간이므로 이러한 벡터 공간에 Fisher linear discriminant를 적용하면 클래스간의 더욱 효과적인 분리가 이루어져 인식률을 획기적으로 향상시킨다. 또한, SKKUface 방법은 클래스간 분산(between-class covariance) 행렬과 클래스내 분산(within-class covariance) 행렬을 계산할 때 문제가 되는 메모리양과 계산 시간을 획기적으로 줄이는 방법을 제안하여 적용하였다. 제안된 SKKUface 방법의 얼굴 인식 성능을 평가하기 위하여 YALE, SKKU, ORL(Olivetti Research Laboratory) 얼굴 데이타베이스를 가지고 기존의 얼굴 인식 방법으로 널리 알려진 Eigenface 방법, Fisherface 방법과 함께 인식률을 비교 평가하였다. 실험 결과, 제안된 SKKUface 방법이 조명 변화, 부분적인 오클루전이 있는 얼굴 영상에 대해서 Eigenface 방법과 Fisherface 방법에 비해 인식률이 상당히 우수함을 알 수 있었다.

• The Journal of Korean Institute for Practical Engineering Education
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• v.3 no.1
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• pp.56-61
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• 2011

As IT technology improves, software is being more and more important. Industry demands higher level of programming ability from university graduates. As a result, programming related courses already take higher possession of electronics department curricula. But even though the environment likewise computer laboratory is improved as much, and professors have tried to enhance the quality of their lectures and educational results, still programming education does not match the demand of our society and industry. In this paper, we introduce the overview of programming education in electronics department, KUT and discuss problems in programming language education especially for the 1st year students, since programming education to the 1st year university students becomes one of the most important part as it deals with fundamentals on programming language and we suggest its improvement directions in regards with students, teaching materials, professors, class size, and class hours.

• Parasites, Hosts and Diseases
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• v.45 no.3
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• pp.239-243
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• 2007

Many allergists are currently focusing on the development of new diagnostic tools, and are attempting to improve both the sensitivity and specificity. A multiple allergen simultaneous test-chemiluminescent assay (MAST-CLA) is one of the most popular diagnostic tools used in the Republic of Korea. However, there remains controversy among allergists with regard to the cut-off point for a positive result. The present study was conducted in order to determine the validity of MAST-CLA as compared with that of the skin prick test, with particular emphasis on arthropod allergens, on the basis of percentage agreement rates and k-values, and also to suggest the optimal positive cutoff points using receiver operating characteristic (ROC) curves. The study was conducted with 97 subjects (54 men, 43 women). Optimal individual cut-off points were calculated as follows; class II for Dermatophagoides farinae, class I for Dermatophagoides pteronyssinus, and trace for a cockroach mix. These findings suggest that attempting to apply optimal individual cut-off points will be a good way of improving diagnostic tests, particularly MAST-CLA.

• ETRI Journal
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• v.36 no.6
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• pp.924-930
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• 2014

This paper presents a $0.13{\mu}m$ CMOS 3-level envelope delta-sigma modulation (EDSM) RF signal generator, which synthesizes a 2.6 GHz-centered fully symmetrical 3-level EDSM signal for high-efficiency power amplifier architectures. It consists of an I-Q phase modulator, a Class B wideband buffer, an up-conversion mixer, a D2S, and a Class AB wideband drive amplifier. To preserve fast phase transition in the 3-state envelope level, the wideband buffer has an RLC load and the driver amplifier uses a second-order BPF as its load to provide enough bandwidth. To achieve an accurate 3-state envelope level in the up-mixer output, the LO bias level is optimized. The I-Q phase modulator adopts a modified quadrature passive mixer topology and mitigates the I-Q crosstalk problem using a 50% duty cycle in LO clocks. The fabricated chip provides an average output power of -1.5 dBm and an error vector magnitude (EVM) of 3.89% for 3GPP LTE 64 QAM input signals with a channel bandwidth of 10/20 MHz, as well as consuming 60 mW for both channels from a 1.2 V/2.5 V supply voltage.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.5
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• pp.405-411
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• 2010

A 5kW class SOFC cogeneration system consisted of a hot box part, a cold BOP (balance of plant) part, and a hot water reservoir. The hot box part contained a stack, a fuel reformer, a catalytic combustor, and heat exchangers. A cold BOP part was composed of blowers, pumps, a water trap, and system control units. A 5kW stack was designed to integrate 2 sub-modules. In this paper, the 5kW class SOFC system was operated using 2 short stacks connected in parallel to test the sub-module and the system. A short stack had 15 cells with $15{\times}15 cm^2$ area. When a natural gas was used, the total power was about 1.38 kW at 120A. Because the sub-modules were connected in parallel and current was loaded using a DC load, voltages of sub-modules were same and the currents were distributed according to the resistance of sub-modules. The voltage of the first stack was 11.46 V at 61A and the voltage of the second stack was 11.49V at 59A.

• Journal of Korean Elementary Science Education
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• v.24 no.4
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• pp.435-442
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• 2005

For this study we conducted a survey far elementary students from 3rd to 6th grade. We performed a frequence test using statistic program and the cross-tabs between gender and grade. We then conducted a thorough interview with the students, after constructing several meaningful questions reflecting the results of survey. As a result of this study, it was critical to arrange interesting inquiry activities in order to foster student's preference for science and attract them to get involved in the science class. We found that teachers were needed to be more flexible to make a group during the classes and teachers would succeed to reflect student's characteristics. In addition, it is necessary for the teachers to refrain from excessive advising or immoderate interrupting student's experiment activity. We conclude that only when the improvements in the curriculum for science education should be made, teachers would allow students to recognize its significances by themselves, and let them follow the inquiring process during the laboratory class for themselves.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1169-1171
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• 2003

This paper presents a 1.6[kW]class single phase high power factor(HPF) pulse width modulation(PWM) boost rectifier featuring soft commutation of the active switches at zero current. It incorporates the most desirable properties of conventional PWM and soft switching resonant techniques. The input current shaping is achieved with average current mode control and continuous inductor current mode. This new PWM converter provides zero current turn on and turn off of the active switches, and it is suitable for high power applications employing insulated gate bipolar transistors(IGBT'S). The principle of operation, the theoretical analysis, a design example, and experimental results from laboratory prototype rated at 1.6[kW] with 400[Vdc] output voltage are presented. The measured efficiency and the power factor were 96.2[%] and 0.99[%], respectively, with an input current Total Harmonic Distortion(THD) equal to 3.94[%], for an input voltage with THD equal to 3.8[%], at rated load.

• Journal of Sensor Science and Technology
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• v.21 no.2
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• pp.103-108
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• 2012

Radiofrequency(RF) signal is a key medium to the most of the present wireless communication devices including RF identification devices(RFID) and smart sensors. However, the most critical barrier to overcome in RFID application is in the failure rate in detection. The most notable improvement in the detection was from the introduction of EPC Class1 Gen2 protocol, but the fundamental problems in the physical properties of the RF signal drew less attention. In this work, we focused on the physical properties of the RF signal in order to understand the failure rate by noting the existence of the ground planes and noise sources in the real environment. By using the mathematical computation software, Maple, we simulated the distribution of the electromagnetic field from a dipole antenna when ground planes exist. Calculations showed that the dark area can be formed by interference. We also constructed a test system to measure the failure rate in the detection of a RFID transponder. The test system was composed of a fixed RFID reader and an EPC Class1 Gen2 transponder which was attached to a scanner to sweep in the x-y plane. Labview software was used to control the x-y scanner and to acquire data. Tests in the laboratory environment showed that the dark area can be as much as 43 %. One who wants to use RFID and smart sensors should carefully consider the extent of the dark area.