• Journal of the Ergonomics Society of Korea
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• v.22 no.3
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• pp.75-91
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• 2003

Evaluation of repetitiveness for hand-intensive tasks is essential to determine the level of risk for upper-extremity musculoskeletal disorders at the workplace. Many measures and methods have been introduced for repetitiveness assessment: however, our understanding of the differences among these measures and methods is lacking. The present study compared the repetitiveness measures and measurement/analysis methods to help practitioners apply the proper repetitiveness assessment methodology in the workplace. By reviewing 51 studies of repetitiveness assessment, measures and corresponding measurement/analysis methods were surveyed. Of the repetitiveness measures, two types of dimensions (frequency and time) and corresponding types of analysis scopes were identified. According to the dimensional and analysis-scope types. the repetitiveness measures were categorized and then the surveyed studies were counted for each measure. It is identified that frequency measures have used 2.7 times higher than time measures and the frequency of wrist motions has been most frequently used in repetitiveness assessment. Furthermore, the measurement methods were categorized into objective and subjective methods, and the analysis methods into statistical and spectral methods. Lastly, eight factors (accuracy, reliability. sensitivity. efficiency. ease of use. applicability. interference. and robustness) were listed to be considered in selecting the appropriate assessment methodology.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.19 no.1
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• pp.28-37
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• 2008

Objectives : This study was conducted in order to examine the reliability and validity of the Children's Color Trails Test (CCTT). The objective of the study was also to provide the Korean normative data for the CCTT. Methods : Normative samples consisted of 766 children and adolescents living in Seoul and aged from 5 to 15 years. Eighty children who were diagnosed with ADHD, based on the DSM-IV criterion, were recruited from Seoul National University Children's Hospital. Among them, 46 ADHD children were receiving medication, while 34 children were drug-free. Results : The scores of the CCTT were significantly correlated with those of the Stroop test. Three factors were extracted through factor analysis-visual tracking and cognitive flexibility, distractibility and susceptibility to interference, and simple attention and impulsivity. The completion time of the CCTT for all children tended to decrease as age increased. There were significant differences in the CCTT scores between the ADHD group receiving medication, the ADHD-drug free group and the normal groups. The CCTT also showed sound test-retest reliability. These results confirmed the reliability and validity of the CCTT. Finally, we provided the Korean normative data for the CCTT. Conclusion : These results suggest that the CCTT is a reliable and valid test, which can be used to assess frontal function related to child psychiatric disorders in Korean children.

• Aerospace Engineering and Technology
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• v.3 no.2
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• pp.72-80
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• 2004

LOX pump is one of the sub-assemblies constructing turbopump unit. In the current study, static structural analysis on such rotating parts as impeller and inducer has been carried out. Three major factors which can affect the structural stability of the rotating parts of LOX pump, are temperature, pressure, and centrifugal force. The effect of each factor was preliminarily investigated, then the analysis under the consideration of the combined loading conditions has been carried out. The major factor that affects the structural stability was proved to be temperature. The analyses of the combined cases showed that the designed impeller and inducer had reasonable safety margins, which means that the impeller and the inducer will be stable in static structural strength. Although there was no problem in the structural strength of the impeller and the inducer, a model analysis should be followed in order to verify the interference between the rotating part and the inner surface of casing.

• Human Ecology Research
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• v.54 no.5
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• pp.475-485
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• 2016

This study explored mothers' and grandmothers' perception regarding child rearing practices as overprotective behaviors for first to third grade levels of elementary school. The study was conducted on 202 mothers and grandmothers of first to third grade elementary school students. Questionnaires were made with 40 questions on overprotection behaviors selected from the existing questions for preschooler, high grade elementary students, and youth. The questionnaires were distributed to target subjects to answer how they would perceive when each of question is applied to their lower grade elementary students. Based on the collected responses and the factor analysis, it was found out that the overprotective behaviors were classified into four factors such as "reduction in independence," "over-sensitiveness to safety," "interference in daily life," and "health anxiety." There were significant differences in the perception of the overprotective behavior by the subjects depending on the generations, features of children and mothers. This study focused on the lower grade elementary school students who have been removed from studies due to the lack of intervention measures. It has the implication in that the findings of the study can give the basic data for the development of the scale on overprotective behaviors in lower grade elementary school students.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.3
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• pp.875-880
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• 2015

Mediator 19 (Med19) is a component of the mediator complex which is a coactivator for DNA-binding factors that activate transcription via RNA polymerase II. Accumulating evidence has shown that Med19 plays important roles in cancer cell proliferation and tumorigenesis. The involvement of Med19 in sensitivity to the chemotherapeutic agent cisplatin was here investigated. We employed RNA interference to reduce Med19 expression in human non-small cell lung cancer (NSCLC) cell lines and analyzed their phenotypic changes. The results showed that after Med19 siRNA transfection, expression of Med19 mRNA and protein was dramatically reduced (p<0.05). Meanwhile, impaired growth potential, arrested cell cycle at G0/G1 phase and enhanced sensitivity to cisplatin were exhibited. Apoptosis and caspase-3 activity were increased when cells were exposed to Med19 siRNA and/or cisplatin. The present findings suggest that Med19 facilitates tumorigenic properties of NSCLC cells and knockdown of Med19 may be a rational therapeutic tool for lung cancer cisplatin sensitization.

• Journal of Korean Academy of Nursing
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• v.30 no.2
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• pp.293-306
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• 2000

Providing care to the dementia elderly with behavioral problem is a major issue in nursing homes today. This study was aimed to explore the nursing staffs′ response to aggressive dementia patients, and the effect that the aggressive behavior had on Nsgstaff. The interviews used a semi-structured questionnaire are were carried out from May to July, 1999. The subjects were 23 nursing personnel working in the nursing homes for dementia elderly. The result are as follows; 1. The types of aggressive behavior cited by the subjects was "physical", "linguistic", and "sexual". 2. The factors that caused the behavior were "symptoms of disease", "under- conditioning", "context of nursing care", "unsatisfied need", "relationship to other patients", "change of outer environment", and "invasion of one′s own privacy". 3. The response of the subjects were "unhappiness", "stress", "anger", "exaggeration", "anxiety", and "fear". 4. The management strategies listed by nursing personnel used to alleviate aggressive behavior were "ignorance" "patience" "leaving the area" "soothing sounds" "verbal punishment" "restriction and isolation" and "various management skill appliance" "adaptation". 5. The effect that aggressive behavior and were "disturbance of relationship to elderly" "decline in the amount and quality of nursing care" "interruption of task performance" "job exhaustion" "desire to leave the job" "physical impact" "stress on the cognition of others" "anxiety about health and one own future" "interference to family life′. The findings of this study will be useful in understanding the difficulties of nursing personnel when confronting the aggressive behavior of dementia partients. It also is useful as basic data in preparing efficient intervention program for these difficulties.

• Journal of Advanced Navigation Technology
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• v.13 no.6
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• pp.907-915
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• 2009

Spectrum sharing between wireless systems becomes a critical issue due to emerging new technologies and spectrum shortage. Recently, IMT system has been allocated in the same frequency C band (3400-4200MHz) along with FSS services on co-primary basis, which means that harmful interference probability may be inspired. In this paper, to estimate the spectrum sharing between IMT and FSS systems, the minimum separation distances have been evaluated considering major factors such as the clutter loss in some areas and the elevation angle of FSS earth station, and using I/N=-10dB which is fundamental criterion for coexistence.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.357-360
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• 2007

An asset tracking using wireless sensor network is concerned with geographical locations of sensor nodes. The limited size of sensor nodes makes them attractable for tracking service, at the same time their size causes power restrictions, limited computation power, and storage restrictions. Due to such constrained capabilities, the wireless sensor network basically assumes the failure of sensor nodes. This causes a set of concerns in designing asset tracking system on wireless sensor network and one of the most critical factors is location uncertainty of sensor nodes. In this paper, we classify the location uncertainty problem in asset tracking system into following cases. First, sensor node isn't read at all because of sensor node failure, leading to misunderstanding that asset is not present. Second, incorrect location is read due to interference of RSSI, providing unreliable location of asset. We implemented and installed our asset tracking system in a real environment and continuously monitored the status of asset and measured error rate of location of sensor nodes. We present experimental results that demonstrate the location uncertainty problem in asset tracking system using wireless sensor network.

• Journal of the Optical Society of Korea
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• v.10 no.1
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• pp.1-10
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• 2006

Optical transparency and high diffraction efficiency are two essential factors for high performance of the photopolymer. Optical transparency mainly depends on the miscibility between polymer binder and photopolymerized polymer, while diffraction efficiency depends on the refractive index modulation between polymer binder and photopolymerized polymer. For most of organic materials, the large refractive index difference between two polymers accompanies large structural difference that leads to the poor miscibility and thus poor optical quality via light scattering. Therefore, it is difficult to design a high-performance photopolymer satisfying both requirements. In this work, first, we prepared a new phase-stable photopolymer (PMMA) with large refractive index modulation and investigated the optical properties. Our photopolymer is based on modified poly (methyl methacrylate) as a polymer binder, acryl amide as a photopolymerizable monomer, triethanolamine as initiator, and yellow eosin as a photosensitizer at 532 nm. Diffraction efficiency over 85% and optical transmittance over 90% were obtained for the photopolymer. Second, Organic-inorganic nanocomposite films were prepared by dispersing an aromatic methacrylic monomer and a photo- initiator in organic-inorganic hybrid sol-gel matrices. The film properties could be controlled by optimizing the content of an organically modified silica precursor (TSPEG) in the sol-gel matrices. The photopolymer film modified with the organic chain (TSPEG) showed high diffraction efficiency (> 90%) under an optimized condition. High diffraction efficiency could be ascribed to the fast diffusion and efficient polymerization of monomers under interference light to generate refractive index modulation. The TSPEG modified photopolymer film could be successfully used for holographic memory.

• Journal of the Optical Society of Korea
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• v.18 no.5
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• pp.459-465
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• 2014

Visible light communications (VLC) using the intensity modulation of light-emitting diodes (LEDs) provides a new communication medium to overcome the shortage of radio spectrum, and allows reuse of LED lighting infrastructures. Orthogonal frequency-division multiplexing (OFDM) was introduced to VLC for its merits in mitigating the fading effects resulting from delay spread, and in avoiding low-frequency ambient interference. Noise and clipping are two major factors that degrade the performance of OFDM in VLC. A larger signal easily overcomes noise, but experiences impairment by clipping. Therefore, degradation due to clipping has a trade-off relationship with that due to noise, depending on the signal amplitude of OFDM. In this paper, the optimal signal amplitude in the trade-off is obtained by simulation when the dimming and LED intensity are given. The former indicates a user's requirement for lighting, and the latter represents the channel quality. The required LED intensity-to-noise ratio, as the channel quality that guarantees dimming as well as an adequate bit-error rate (BER), is also discussed.