• 대한의용생체공학회:의공학회지
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• 제39권3호
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• pp.124-133
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• 2018

We tried to investigate the changes in cortical activities according to emotional valence states during watching video clips. We examined the neural basis of two emotional states (positive and negative) using spectral power analysis and brain functional connectivity analysis of cortical current density time-series reconstructed from high-density electroencephalograms (EEGs). Fifteen healthy participants viewed a series of thirty-two 2 min emotional video clips. Sixty-four channel EEGs were recorded. Distributed cortical sources were reconstructed using weighted minimum norm estimation. The temporal and spatial characteristics of spectral source powers showing significant differences between positive and negative emotion were examined. Also, correlations between gamma-band activities and affective valence ratings were determined. We observed the changes of cortical current density time-series according to emotional states modulated by video clip. Gamma-band activities showed significant difference between emotional states for thirty seconds at the middle and the latter half of the video clip, mainly in prefrontal area. It was also significantly anti-correlated with the self-ratings of emotional valence. In addition, the gamma-band activities in frontal and temporal areas were strongly phase-synchronized, more strongly for negative emotional states. Cortical activities in frontal and temporal areas showed high spectral power and inter-regional phase synchronization in gamma-band during negative emotional states. It is inferred that the higher amygdala activation induced by negative stimuli resulted in strong emotional effects and caused strong local and global synchronization of neural activities in gamma-band in frontal and temporal areas.

• Journal of Microbiology and Biotechnology
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• 제19권7호
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• pp.718-726
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• 2009

The objective of this study was to develop and validate secondary models that can predict growth parameters of L. monocytogenes Scott A as a function of concentrations (0-3%) of a commercial potassium lactate (PL) and sodium diacetate (SDA) mixture, pH (5.5-7.0), and temperature (4-37DC). A total of 120 growth curves were fitted to the Baranyi primary model that directly estimates lag time (LT) and specific growth rate (SGR). The effects of the variables on L. monocytogenes Scott A growth kinetics were modeled by response surface analysis using quadratic and cubic polynomial models of the natural logarithm transformation of both LT and SGR. Model performance was evaluated with dependent data and independent data using the prediction bias ($B_f$) and accuracy factors ($A_f$) as well as the acceptable prediction zone method [percentage of relative errors (%RE)]. Comparison of predicted versus observed values of SGR indicated that the cubic model fits better than the quadratic model, particularly at 4 and $10^{\circ}C$. The $B_f$and $A_f$for independent SGR were 1.00 and 1.08 for the cubic model and 1.08 and 1.16 for the quadratic model, respectively. For cubic and quadratic models, the %REs for the independent SGR data were 92.6 and 85.7, respectively. Both quadratic and cubic polynomial models for SGR and LT provided acceptable predictions of L. monocytogenes Scott A growth in the matrix of conditions described in the present study. Model performance can be more accurately evaluated with $B_f$and $A_f$and % RE together.

• 한국통신학회논문지
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• 제3권1호
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• pp.18-25
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• 1978

반도체 소자에서 생기는 1/f 형의 잡음의 근원이 무엇인가에 대해 지금까지 여러 이론이 나왔다. 그중에도 Mcwhorter's Surface model이 대표적인 이론이었다. 그러나 Hooge는 이론에 반기를 들고 나왔다. Hooge의 이론에 의하면 thermo cell이나 Concentration cell에서의 1/f-형의 잡음이 표면효과(surface effect)가 아니라는 것이다. 본 논문에서는 이 두 대표적인 이론을 종합검토할 수 있는 Langenvin type의 Boltzmann transport equation에 입각하여 새로운 일반이론을 세웠다. 본 논문에서는 N형 채널을 갖고 있는 금속산화물반도체 전계효과 트랜지스터에서 단일준의 Shockley-Read-Hall recombination center에 의한 단락회로에서 드레인의 1/f-형 잡음스펙트럼을 계산하기 위해 시간에 따라 변화하는 양을 포함시키므로써 각 에너지대의 케리어에 대해 준-페르미준위를 정의할 수 없다고 가정했으므로, 1/f-형의 잡음은 다수케리어 효과에 기인한다고 가정했다. 이러한 가정하에서 유도된 1/f-형의 잡음은 금속산화물반도체 전계효과 트랜지스터에서 1/f-형의 잡음에 중요한 요인들을 모두 보여주었다. : 적주파에서 플렛티유를 나타내지 않았고 채널의 면적 A와 드레인 바이어스 전압 V에 비례하고 체널의 길이 L에 반비례한다. 본 논문의 모델에서는 1/f-응답에서 1/f2에 대한 잡음스트럼의 전이주파수와 P-n 합다이오우드의 surfact center에 관계되는 완화시간(relaxation time)에 대응하는 주파수 사이를 구별하여 설명할 수 있었다. 본 논문의 결과에서 1/f-형 잡음스펙트럼은 격자산란이 주원인이 된다. 금속산화물반도체 전계효과 트랜지스터를 살펴보면 격자산란이 주로 표면에서 일어나기 때문에 1/f-형 잡음이 표면효과라고 말할 수 있다.

• Journal of Radiation Protection and Research
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• 제42권2호
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• pp.83-90
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• 2017

Background: Different cases exist in the measurement of thyroid radiobioassays owing to the individual characteristics of the subjects, especially the potential variation in the counting efficiency. An In situ Object Counting System (ISOCS) was developed to perform an efficiency calibration based on the Monte Carlo calculation, as an alternative to conventional calibration methods. The purpose of this study is to evaluate the applicability of ISOCS to thyroid radiobioassays by comparison with a conventional thyroid monitoring system. Materials and Methods: The efficiency calibration of a portable high-purity germanium (HPGe) detector was performed using ISOCS software. In contrast, the conventional efficiency calibration, which needed a radioactive material, was applied to a scintillator-based thyroid monitor. Four radioiodine samples that contained $^{125}I$ and $^{131}I$ in both aqueous solution and gel forms were measured to evaluate radioactivity in the thyroid. ANSI/HPS N13.30 performance criteria, which included the relative bias, relative precision, and root-mean-squared error, were applied to evaluate the performance of the measurement system. Results and Discussion: The portable HPGe detector could measure both radioiodines with ISOCS but the thyroid monitor could not measure $^{125}I$ because of the limited energy resolution of the NaI(Tl) scintillator. The $^{131}I$ results from both detectors agreed to within 5% with the certified results. Moreover, the $^{125}I$ results from the portable HPGe detector agreed to within 10% with the certified results. All measurement results complied with the ANSI/HPS N13.30 performance criteria. Conclusion: The results of the intercomparison program indicated the feasibility of applying ISOCS software to direct thyroid radiobioassays. The portable HPGe detector with ISOCS software can provide the convenience of efficiency calibration and higher energy resolution for identifying photopeaks, compared with a conventional thyroid monitor with a NaI(Tl) scintillator. The application of ISOCS software in a radiation emergency can improve the response in terms of internal contamination monitoring.

• 한국정보통신학회논문지
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• 제18권6호
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• pp.1407-1412
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• 2014

근적외선 파장대역 850 nm ~ 1000 nm에서 레이저를 검출하기 위해 포토다이오드의 분광감응도를 향상시키고자 본 논문에서 실리콘 기반 고감도 PIN 포토 다이오드를 제작하고 전기적 및 광학적 특성을 분석하였다. 제작된 소자는 TO-18형으로 패키징 하였고 포토다이오드의 전기적 특성으로 역 바이어스 전압이 5V일 때 암전류는 Anode 1과 Anode 2는 약 0.055 nA 의 값을 나타내었으며 정전용약은 0V 일 때 1 kHz 주파수 대역에서 약 19.5 pF, 200 kHz 주파수 대역에서 약 19.8 pF의 적은 정전용약을 나타내었다. 또한 출력신호의 상승시간은 10 V의 전압일 때 약 30 ns의 고속 응답특성을 확인하였다. 광학적 특성 분석으로는 880 nm에서 최대 0.66 A/W의 분광감응도 값을 나타내었고 1000 nm에서는 0.45 A/W로 비교적 우수한 분광감응도를 나타내었다.

• 한국정보통신학회논문지
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• 제18권7호
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• pp.1777-1783
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• 2014

본 연구에서는 전자장비 내방사화 기술의 새로운 효율적 접근방법인 전원제어형 방호장치에서 핵심 기능을 수행하는 고속 반도체 센서를 개발하고 그 특성을 분석하였다. 먼저, 펄스방사선에 의한 다이오드 내부에서의 생성 전하를 계산한 후 TCAD로 모델링하여 $42{\mu}m$ 진성층의 실리콘 에피텍시 웨이퍼 기반의 고속 신호탐지용 PIN 다이오드 센서를 다양한 구조로 설계하였다. PAL의 Test LINAC의 전자빔 변환 감마방사선 4.88E8 rad(Si)/sec에 대한 실측시험에서 소자의 면적에 비례하는 광감도와 응답속도 증가 결과를 얻었으며 포화특성과 소자의 균일성을 기준으로 2mm직경의 센서를 최적으로 판단되었다. 선정 센서를 대상으로 한 펄스감마선 고출력 범위(2.47E8 rad(Si)/sec~6.21E8 rad(Si)/sec)로 선량률 가변시험에서는 개발한 소자가 시험장치의 고 선량률 영역에서 전원제어 신호처리에 충분한 60mA 이상의 광전류 피크값과 함께 350 ns 이하의 고속 응답특성을 가지는 선형적 센서임을 확인하였다.

• 지질공학
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• 제27권2호
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• pp.165-172
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• 2017

본 연구는 델파이 기법을 활용하여 최적화 단면 설계 도출 및 시공중 터널 붕괴위험도 평가를 위해 필요한 평가영향인자를 정립하는 것을 목표로 하였다. 평가영향인자 정립은 문헌조사, 선행연구 및 전문가 집단의 브레인스토밍과정을 통하여 총 5개의 상위분류체계를 구축하였다. 21명의 전문가 패널을 구성하여 총 1, 2, 3차의 델파이 조사 과정을 통해 전문가 판단과정에서의 오류 및 편향을 방지하여 신뢰성을 향상시켰다. 델파이 1차 조사에서는 개방형 설문조사를 통해서 각 전문가 패널의 의견을 수렴하여 총 22개의 평가영향인자 후보군을 도출하였다. 델파이 2차 조사에서는 수집된 총 22개의 평가영향인자 후보군을 대상으로 리커트 7점 척도를 기반으로 중요도 설문을 수행하였으며 타당성 검증을 위해 CVR (Content Validity Ration)분석을 수행하여 부적합한 후보군을 제외하였다. 마지막으로 3차 조사에서는 2차 조사에서 도출된 결과를 가지고 재조사를 수행하였으며, 최종적으로 전문가 답변에 대한 CVR 및 COV (Coefficient of Variation)분석을 수행하여 총 14개의 평가영향인자를 도출하였다.

• 한국치위생학회지
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• 제5권2호
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• pp.279-296
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• 2005

The purpose of this study was to examine what types of experiences dental hygienists underwent with patients who were unapproachable in an effort to find out the latter group's needs and expectations, explore how to treat them of different personality type, and provide better dental services in response to their needs. To attain the purpose, Q-methodology was employed, which made a subjective and systematic assessment of human subjectivity. There were three types of subjectivity among dental hygienists in conjunction with their experiences with patients who were hard to please. Each group whose subjectivity was different also had a different preference for patients, which was not exclusive to one another but unique. Type 1 was "avoiding patients who showed off". Dental hygienists of this type found it unpleasant to treat patients who boasted of their background, position or relations with the head of hospital and wanted to be given special treatment. They avoided those patients, since giving special treatment to specific patients was likely to do damage to others. They believed that better medical services could be provided through mutual concern and good manners between medical personnels and patients. Dental hygienists of type 2 considered it hard to treat patients who were picky and looked at treatment or its outcome negatively. Those who had to be separated from others on account of possible cross-infection or who called for special decontamination methods of dental instruments were also difficult to deal with. Dental hygienists of this type could be said to "avoid picky patients", as they preferred to fare with patients by offering good, faithful treatment rather than by giving special treatment. Dental hygienists of type 3 believed that smooth and successful treatment hinged on mutual trust, confidence and collaboration between medical personnels and patients. According to them, patients who choose a specific hospital or a particular medical team at their own option have to cooperate if necessary, listen carefully to medical personnels and treat them without any hostility or bias. Therefore, they could be said to "avoid patients who were not cooperative".

• 한국프랜차이즈경영연구
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• 제11권2호
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• pp.41-51
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• 2020

Purpose: Fast food franchise companies are trying a variety of innovative services to increase their competitiveness in response to changes in population composition in the fast food market and rapid changes in consumption trends due to technological development. From this point of view, franchise companies that have focused on offline store operations are providing O2O (offline to online) service as a core service for customer convenience. This new attempt is a strategy to increase loyalty by applying an interaction method based on understanding the characteristics of new generation consumers. However, existing studies are focused on the relationship between O2O service and acceptance, so very little is known about how O2O service affects customer loyalty. Therefore, this study examines the impacts of customer involvement and relative advantages of fast food O2O service on customer brand engagement (cognitive and affective engagement) and store loyalty for MZ(Millennials - Z) generations. Research design, data, and methodology: In order to achieve the purposes of this research, several hypotheses were developed. The data were collected from 247 questionnaires in their 16-30s and were analyzed using SPSS 22.0 and SmartPLS 3.0 program. Measurement model analysis was carried out to assess convergent and discriminant validity. Also, common method bias was tested using the values of VIF (variance inflation factor). The hypotheses was tested using structural equation modeling. Result: First, involvement has a positive effect on cognitive and affective engagement. Second, relative advantages have has a positive effect on cognitive and affective engagement. Third, cognitive influences affective engagement. Finally, both cognitive and affective engagement affect store loyalty, but affective engagement has a stronger effect on store loyalty than cognitive engagement. Conclusions: In the process of consumer-brand interaction, it was confirmed that store loyalty was influenced by cognitive and affective engagement sequentially. However, the results show that affective engagement has a relatively stronger on store loyalty than cognitive engagement. Therefore, it is necessary to establish an O2O service strategy to maintain long-term loyal customers by inducing cognitive participation with high-involved consumer, as well as affective interaction, in order to obtain new customers and increase customer loyalty.

• 한국프랜차이즈경영연구
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• 제13권1호
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• pp.35-46
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• 2022

Purpose: With the rapid changes in the technical development and the trend of consumption trend, the convenience store industry is facing an unprecedented competitive situation in the consumption environment where the boundary between online and offline is broken due to the stagnation of offline distribution channels and the spread of online shopping. The biggest innovation strategy of the major convenience store brands in recent years are introducing the O2O (Online to Offline) platform and presenting new products and services beyond the boundaries of online and offline to transform themselves into Omni Channel stores. The study is designed to analyze the effect of innovativeness of convenience store as a stimulus in O2O platform which customers perceive on store loyalty, the final response to external stimuli, through customer engagement with convenience store brands. Specifically, the innovativeness of convenience stores was divided into types of core activities in corporate marketing and focused on innovations in services, products(proposals), promotions and experiences. Research design, data, and methodology: Various hypotheses have been developed to achieve this research purpose. The data were collected from 1,128 questionnaires the age between 15 and 60 who had experience using retail store apps and delivery apps and were analyzed using SPSS 22.0 and SmartPLS 3.3.7 program. Measurement model analysis was carried out to assess convergent and discriminant validity. Also, common method bias was tested using the values of VIF (variance inflation factor). The hypotheses were tested using structural equation modeling with SmartPLS 3.3.7 program. Results: First, service innovation has a positive effect on cognitive engagement. Second, product, promotion and experience innovation have a positive effect on cognitive and affective engagement. Third, cognitive influences affective engagement. Finally, both cognitive and affective engagement affect store loyalty, but affective engagement has a stronger effect on store loyalty than cognitive engagement. Conclusions: All four types of innovation and cognitive engagement have a positive effect on emotional engagement, which has a stronger effect on store loyalty than cognitive engagement. Thus, while innovation can build loyalty through emotional engagement, innovation strategies must be designed and pursued with caution in terms of impact through cognitive engagement may not achieve the planned goals.