• 한국물환경학회지
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• 제26권3호
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• pp.518-524
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• 2010

Continuous removal of organic matters (CROM) using freshwater bivalve Anodonta woodiana was operated to evaluate the effect of water current on the water quality improvement (clearance) of eutrophic lake. The CROM system comprised three treatment steps such as flow control, treatment and analysis, and operated at the two different currents ($24L\;h^{-1}$ and $48L\;h^{-1}$) with mussels at density of $312.5indiv.\;m^{-2}$ for 12 consecutive days. Water quality including suspended solids (SS) and chlorophyll-a (Chl-a) was daily measured at the same time. Results indicate that although both the system strongly decreased the concentration of SS and chl-a, a slow CROM system was more effective to diminish the SS contents than a fast CROM system; 82% and 66%, respectively (ANOVA, P<0.0001). Clearance rates, based on chl-a, were also significantly higher in a slow system than a fast system (ANOVA, P<0.0001), although the mussel mortality was conversely. In both systems, there showed a remarkable excretion of dissolved inorganic nutrients (i.e. $NH_3-N$ and $PO_4-P$), while a slow CROM system was higher than a fast system, significantly (ANOVA, P<0.0001). Therefore, it may suggest that a slow current CROM system is more suitable to maximize the efficacy of water quality improvement, but further study is needed to diminish the mortality of mussel and to reuse the nutrient released during the operation.

• 생태와환경
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• 제42권3호
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• pp.317-330
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• 2009

패류를 이용한 오염하천의 수질개선 가능성을 확인하고자 CROM기술을 응용한 S-CROM기법을 개발하고 현장에 직접 적용하였다. 실험은 하천에 형성된 소형 보에서 실시하고 자연유속을 그대로 이용하였으며, 패류의 섭식활동을 위해 현장의 퇴적물을 첨가하였다. 실험은 처리조를 현장수(대조군), 현장수+퇴적물(대조군), 현장수+퇴적물+패류 30개체 (D1), 현장수+퇴적물+패류 60개체 (D2) 등 4가지로 구성하고, 유속은 450mL $min^{-1}$, 시료채취는 12시간(주, 야)간격으로 실시하였다. 환경요인으로는 현장에서 직접 수온, pH, DO, 전기전도도, 탁도 등을 측정하였고 시료를 채취하여 Chl-$\alpha$, SS, TN, TP, $NO_2$-N, $NO_3$-N, $NO_4$-N, $PO_4$-P, BOD, 식물플랑크톤 등을 분석하였다. 실험결과 유기물 제어능은 패류밀도와 처리시간에 따라 차이를 보였는데, 최대효과는 운영 2일째, 낮 동안 그리고 고밀도 처리군에서 나타났으며, 부유물질 (57%)과 조류(72%)의 감소를 보였다. 고농도의 암모니아와 인산을 배출하였던 CROM(김 등, 2009)보다 뚜렷하게 낮은 수준을 보였으며, 패류의 밀도효과는 유의하지 않았다. 비록 S-CROM이 CROM에 비하여 낮은 제어율을 보였으나 이는 상대적으로 낮은 패류밀도 및 빠른 유속 등이 원인으로 판단되었다. 따라서 S-CROM를 이용한 하천의 유기물 제어는 하천환경과 패류밀도를 적절하게 조합한다면 높은 수질개선 효과를 기대할 수 있을 것으로 사료되었다.

• 생태와환경
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• 제42권2호
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• pp.161-171
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• 2009

국내산 담수 이매패 펄조개를 이용하여 부영양 저수지의 표층수를 실험실로 유입 처리하고 처리수는 다시 저수지로 환원하는 이른바 '흐름형 유기물 제어'(CROM: continuous removal of organic matters) 기술을 개발하고 하천에서 채취한 모래퇴적물의 첨가가 유기물 제어와 수질에 어떠한 영향을 주는지 조사하였다. CROM은 크게 저류조, 조정조, 처리조, 분석조 등으로 이루어졌으며, 실험은 처리조에 현장수, 현장수+모래, 현장수+패류, 현장수+모래+패류 등을 각각 구성하여 유업속도는 18${\sim}$25 L $h^{-1}$ 패류밀도는 486.1 indiv. $m^{-2}$, 수온은 15${\sim}$22$^{\circ}C$ 범위에서 13일간 실시하였다. 유기물 및 수질 변화를 확인하기 위하여 매일 동일한 시간에 수온, pH, DO, 전도도, 탁도, 염분도, 엽록소 a, 부유물질, TN, TP, $NO_2$, $NO_3$, $NH_3$, $PO_4$ 등을 측정하거나 채수하여 곧바로 분석하였다. 연구결과, 미처리수의 반송이 패류의 유기물 제어에 큰 영향을 미치지 않았으며 퇴적물의 첨가에 상관없이 실험기간 동안 80% 이상 유기물(부유물질 빛 ChI-a)을 감소시켰으나 높은 농도의 암모니아와 인산 등을 배출하였다. 결국 한국산 이매패 펄조개를 이용한 CROM 운영효과는 매우 뚜렷하였으나 장기간 운영시 유기물 제어능 및 패류 생존율에 미치는 다른 요인들-수온, 미생물, 세정주기 등의 변화가 예상되며, 처리수에 대한 처리 및 활용에 대한 다각적인 연구가 뒤따라야 할 것으로 사료되었다.

• 생태와환경
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• 제42권3호
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• pp.350-363
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• 2009

부영양 저수지의 수질개선을 목적으로 연속형 유기물제어(CROM)기술을 이용하여 이미 제어능이 밝혀진 국내산 이매패 말조개와 펄조개를 대상으로 이종간 또는 동종간의 유기물 섭식 특성을 비교 조사하였다. CROM은 매일 저수지 표층수를 직접 실내로 유입하였으며 저장소 및 조절조, 처리조, 분석조 등으로 구성하였다. 섭식실험은 온도와 광도가 일정하게 조절된 실험실에서 실시하였으며, 패류 처리 후 여과율, 제어능, 수질(영양염) 및 배설물 생산량 등을 측정하였다. 실험결과 패각길이가 비슷할 경우 이종간에 유기물 제어능은 서로 비슷하였으나 여과율의 경우에는 말조개가 더 높게 나타났다. 동일종(동밀밀도)내에서는 패각길이가 긴 개체들이 더 높은 제어능을 나타냈으며, 반대로 여과율은 패각길이가 짧은 개체가 높았다. 한편 동일종에서 처리밀도가 다를 경우 저밀도 처리군이 고밀도 처리군 보다 더 높은 여과율을 나타냈다. 배설물 생산은 여과율과 유사한 패턴을 보였으며 처리밀도와 먹이농도 변화가 배설물 생산에 영향을 미치는 것으로 나타났다. 두 종류의 패류는 평균 70% 이상의 뚜렷한 유기물(Chl-$\alpha$, SS) 제어율을 나타냈으며 섭식활동에 따른 $NH_4$-N나 $PO_4$-P과 같은 무기영양염의 배출량은 패각길이나 처리밀도에 따라 크게 영향을 받는 것으로 밝혀졌다. 결론적으로 CROM기술을 이용한 부영양 저수지의 유기물 제어는 적절한 패류의 종류나 밀도의 결정을 통하여 충분히 현장에 적용 가능한 생물학적 기법으로 판단되며, 부산물 처리 및 자원화를 비롯한 추후 연구가 필요하다고 사료되었다.

• 대한통합의학회지
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• 제4권4호
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• pp.83-90
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• 2016

Purpose : Recommended posture according to the location of operating teeth have been standardized in dental clinic to prevent musculoskeletal disorder. However, clinicians do not comply with this rule in many cases. This study investigated the effects of operating posture on cranio-cervical range of motion (CROM) and muscles activity of neck and upper extremity. Methods : Sixteen healthy dental hygiene students were participated. During operating posture (3 recommended and 3 experimental postures which were set front, side, back, respectively), CROM in the fronal and sagittal plane were measured by Cervical Range of Motion Instrument and muscle activities of Sternocleidomastoid, upper trapezius, middle deltoid, extensor carpi radialis, brachioradialis, and abductor pollicis brevis were measured by Pocket EMG system. Result : CROM were significantly decreased in recommended posture in comparison with experimental posture (p<.05). In addition, muscle activity of middle deltoid was significantly decreased in recommended front posture. Moreover, brachioradialis and extensor carpi radialis showed the same result in recommended back posture (p<.05). Conclusion : Recommended posture is close to neutral posture and to reduce muscle fatigue and overuse, which may considered as a preventing musculoskeletal disorder and partially explain its efficacy in dental clinic.

• International Journal of Computer Science & Network Security
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• 제22권3호
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• pp.355-363
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• 2022

This paper presents the modeling for islanded hybrid AC/DC microgrid and the verification of the proposed supervisory controller for energy management for this microgrid. The supervisory controller allows the microgrid system to operate in different power flows through the proposed control algorithm, it has several roles in the management of the energy flow between the different components of the microgrid for reliable operation. The proposed microgrid has both essential objectives such as the maximum use of renewable energies resources and the reduction of multiple conversion processes in an individual AC or DC microgrids. The microgrid system considered for this study has a solar photovoltaic (PV), a wind turbine (WT), a battery (BT), and a AC/DC loads. A small islanded hybrid AC/DC microgrid has been modeled and simulated using the MATLAB-Simulink. The simulation results show that the system can maintain stable operation under the proposed supervisory controller when the microgrid is switched from one operating mode of energy flow to another.

• Journal of Oral Medicine and Pain
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• 제20권2호
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• pp.361-376
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• 1995

The purpose of this study was to investigate the relationship between the head and neck postre and the cervical curvature, especially in forward head postrue(FHP). Sixty patients with craniomandibular disorders and thirty dental students without any signs and symptoms of craniomandibular disordres participated in this study as patient groups and sa control group, respectively. The author evaluated the head and neck posture of all subjects by plumb line and CROM( Cervical Ragne of Motion), and had taken cephaograph in natural head position. On the cephalograph the angle of cervical inclination formed by true horizntal plane and 4th cervical vertebra(C4) and the radius of cervical curvature from C1 to C5 were measured. A specially designed ruler was used for measuring cervical curvature. Occlusal contac number and force with T-scan system, electromygraphic activity of cervical muscles with Bio-EMG, and distance of freeway space with Bio-ECN were recorded, respectively. The collected data were processed by SAS/STAT progrm. The obtained results were as follows : 1. In subjects with longer radius which was less cervical curvature, head positioned more anteriorly than subjects with smaller radius, and they showed slightly straight cervical vertebra. 2. Between the patients and the control group, there were no differences in cervical curvature, in forward head position by plumb line and in CROM. But the patient group had a greater cervical inclination than the control group had. 3. There were positive correlation between cervical curvature and forward head position by plumbline,between forward head position y plumb line and that by CROM in patient group. The cervical inclination, however, had negative correlation with cervical curvature, and with forward head postion by plumb line, respectively. 4. In case of showing more cervical curvature and more forward head position by plumb line the head position was defined as forward head posture. In patient group, subjects without forward head posture showed greater posterior teeth contact force than subjects with forward head posture, but in control group, there were no difference between the two subjects. 5. There were higher electromyographic activity in almost all muscles and smaller freeway space in induced forward head posture than those in natural head position in subjects without forward head posture. In conclusion, head position of patients with craniomandibular disorders were not more anterior than that of normal control person, but they had tendency to head extension. From the result of this study, forward head posture could be defined as posterior rotation of upper cervical segment with a straight lower cercial segment due to loss of normal lordosis.

• Journal of Oral Medicine and Pain
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• 제19권1호
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• pp.137-149
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• 1994

This study was performed to investigate the relationship between Forward Head Posture(FHP) and Craniomandlbular Disorders(CMDs). Many studies reported that there was some relationship between them, however, there is still controversy. So It Is necessary to observe and compare many more patients with CMDs wirh normal controls. For the study 85 patients with CMDs and 37 dental students were selected as experimentals and controls, respectively. And the experimentals were classified Into two groups, that is, TMJ internal derangement group and muscle disorders group according to clinical diagnosis. For measuring the FHP, CROM(Cervical-Range-of-Notion)was used. This goniometer is composed of three part. First, gravity goniometer for flexion and extension. Second, magnetic compass and yoke for rotational movement. And last, forward head arm and vertebra locator for forward head posture. Next T-Scan, electronic occlusal analyzer, was used for recording of occlusal contact state. Other items such as maximum opening, lateral excursion, Helkimo's anamnestic index, and muscle palpation point from Friction's craniomandibular index were checked clinically by one examiner. The result of this study were as follows : 1. In male, control group showed much more measurement in resting forward head posture than did experimental group. But there were not significant differences between groups in female subject. From this results, the author contended that CROM is new measuring system and differ from other goniometers in some aspect, so that results should be re-evaluated 2. Mean value of maximum mouth opening in nearly all groups were greater than 40mm. and mouth opening had a significant correlation with occlusal force and with anamnestic index both sex. 3. Mean value of palpation point had not any correlationship with forward head posture in both sex, but there was significant difference between upper and lower group by rounded shouldes. 4. In summary, there was no significant relationship between forward head posture and sign and symptom of Craniomandibular Disorders.

• 대한통합의학회지
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• 제5권2호
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• pp.83-90
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• 2017

Purpose : The purpose of this study was to investigate the correlation between shoulder gradient, range of motion of the neck, and subjective pain level of the potential risk group of smart-phone addiction. Methods : The subjects of this study were 90 women's who had potential risk of smart-phone addiction. VAS was used to measure subjectively pain intensity. Global Postural System was used to measure forward head posture. CROM was used to measure flexion, extension, lateral flexion of cervical range of motion. Results : The results of this study showed that was significant positive correlation between the both shoulder gradient, and cervical range of motion(p<.05). Statistically significant negative correlation between the VAS and left lateral flexion(p<.05). Conclusions : The difference between the gradient of both shoulders increased with the use of smart-phone addiction, and the cervical left lateral flexion decreased as the pain increased. This suggests that recognition on decrease of using smart phone and postural correction is necessary.

• Journal of Oral Medicine and Pain
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• 제20권1호
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• pp.171-183
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• 1995

This study was carried out to investigate the relationship between tensed mandibular positions, muscle tenderness and EMG activity, respectively, and between range of motion of the neck and sternocleidomastoid muscle tenderness. Under stressful conditions, most of people take several types of behavioral patterns. Two of them observed frequently are clenching of teeth and grasping of fist. Prolonged clenching or grasping should increase electromyographic activity of associated muscle, especially muscles of mastication and neck muscles and will cause hyperfunction, dysfunction and muscle pain. So it is necessary to relate EMG activity with muscle pain. The author performed routine clinical examination in 47 patients with Temporomandibular Disorders, especially for presence or absence of muscle tenderness. Mandibular rest position was used as a baseline reference position and two more position in which EMG activity was taken were rest postion with grasping of fist and teeth clenching position. BioEMG of Biopak system (Bioresearch Inc, USA) was used for measuring of integrated EMG in masseter, anterior temporalis, anterior belly of digastic muscle and sternocleidomastoid muscle. To measure of the range of neck motion. CROM(Cervical-Range-of Motion, USA) was used. The obtained results were as follows : 1. EMG activity of all muscles except in masseter was higher in grasping of fist than those in rest position and there were significant correlation in EMG activity between the two position except in anterior belly of digastric muscle. 2. When comparing EMG activity between tender and non-tender muscle, all examined muscles did not show any significant difference. From this data, we could conclude that EMG activity was generally not changed with tenderness, of couse, it might be dependent with degree of muscle tenderness. 3. Number of tender points in examined muscles was also not significantly different between in patients with masticatory muscle disorders and in patients with internal derangement. 4. Cervical posture and range of motion of the neck was not differed significantly between in patients with and in patients without tenderness of sternocleidomastoid muscle.