• The Journal of Korean Academy of Prosthodontics
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• v.31 no.1
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• pp.63-76
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• 1993

The purpose of this study was to investigate the disclusion time and occlusal pattern during lateral movement in normal group and temporomandibular dysfunction (TMD) group. Twenty dental college students of Chosun University without the abnormal occlusion and temporomandibular dysfunction were selected as a normal group, and twenty slight temporomandibular dysfunction (TMD) group and the ten moderate temporomandibular dysfunction (TMD) group classified according to Helkimo's dysfunction index were selected. Occlusal pattern was classified as canine guided occlusion, group functioned occlusion and the other group during lateral movement and disclusion time in lateral movement was measured using T-Scan system. The result were as follows: 1. The disclusion time according to each group were $1.24{\pm}0.58$ sec in normal $1.60{\pm}0.79$ sec in slight TMD group and $2.29{\pm}0.80$ sec in moderate TMD group. There was statistically significant between normal group and moderate TMD group(P<0.01), slight TMD group and moderate TMD group(P<0.05). 2. The distribution of occlusal pattern in normal group was 62.5% (25 side) in canine guided occlusion, 27.5% (15 side) in group functioned occlusion. 3. The distribution of occlusal pattern in slight TMD group was 45% (18side) in canine guided occlusion, 35% (14 side) in group functioned occlusion and 20% (8side) in others and that in moderate TMD group was 15% (3 side) in canine guided occlusion, 35% (7 side) in group funcconed occlusion and 50% (10 side) in other 4. The disclusion time in normal group was $1.05{\pm}0.59$ sec at canine guided occlusion and $1.53{\pm}0.72$ sec at group functioned occlusion. 5. The disclusion time in slight TMD group was $1.23{\pm}0.75$ sec in canine guided occlusion, $1.50{\pm}0.88$ sec in group functioned occlusion, and $2.61{\pm}0.57$ sec, in the other. There was staistically significant between canine guided occlusion and other(P<0.001)and group functioned occlusion and the other (P<0.05). 6. The disclusion time in moderate TMD group was $1.28{\pm}0.84$ sec in canine guided occlusion, $1.75{\pm}0.58$ sec in group functioned occlusion, and $2.98{\pm}0.08$ sec in the other(P<0.01).

• Journal of Korean Neurosurgical Society
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• v.37 no.1
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• pp.54-58
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• 2005

Objective: The purpose of this study is to determine the time evolution and distribution of cerebral apoptosis using the middle cerebral artery occlusion model in rats. Methods: A total of twenty four male rats - with 2, 3, 4, 6, 8, 12, 24 and 48 hours of middle cerebral artery occlusion respectively - were studied. The terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labeling(TUNEL) method was used for the observation of the apoptotic cells. The apoptotic ratio was calculated and the distribution of apoptosis was inspected in the pyriform cortex, basal ganglia and middle cerebral artery territory cortex. The rats were divided into three groups(Group I : $2{\sim}4$ hours of occlusion, Group II : $6{\sim}$12 hours of occlusion, Group III : $24{\sim}48$ hours of occlusion). Results: In this study, the proportion of apoptosis increased with the duration of middle cerebral artery occlusion and reached a maximum after about 12 hours of middle cerebral artery occlusion. The mean values of the apoptotic ratio were $30.7{\pm}11.3%$ in group I, $60.8{\pm}2.6%$ in group II and $48.7{\pm}0.7%$ in group III. The distribution of apoptosis differed in the pyriform cortex, basal ganglia and middle cerebral artery territory cortex according to the duration of time of the middle cerebral artery occlusion. Conclusion: In the middle cerebral artery occlusion model of the rats, apoptosis is found to increase according to the occlusion time, reaching a peak after 6 hours, and the distribution of apoptosis changed from the pyriform cortex to the basal ganglia and middle cerebral artery territory cortex.

• Journal of Korea Multimedia Society
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• v.18 no.2
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• pp.158-167
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• 2015

This study presents a new method to improve the speed of high quality volume rendering. We improve the speed of ambient occlusion which is one of the global illumination techniques used in traditional volume visualization. Calculating ambient occlusion takes much time because it determines an illumination value of a sample by integrating opacities of nearby samples. This study proposes an improved method for this by using local statistics such as averages and standard deviations. We calculate local statistics for each volume block, a set of nearby samples, in pre-processing time. In the rendering process, we efficiently determine the illumination value by assuming the density distribution as a normal distribution. As the results, we can generate high quality images that combine ambient occlusion illumination with local illumination in real time.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.1
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• pp.23-26
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• 2009

During operations, neurosurgeons usually perform multiple temporary occlusions of parental artery, possibly resulting in the neuronal damage. It is generally thought that neuronal damage by cerebral ischemia is associated with extracellular concentrations of the excitatory amino acids. In this study, we measured the dynamics of extracellular glutamate release in 11 vessel occlusion(VO) model to compare between single occlusion and repeated transient occlusions within short interval. Changes in cerebral blood flow were monitored by laser-Doppler flowmetry simultaneously with cortical glutamate level measured by amperometric biosensor. From real time monitoring of glutamate release in 11 VO model, the change of extracellular glutamate level in repeated transient occlusion group was smaller than that of single occlusion group, and the onset time of glutamate release in the second ischemic episode of repeated occlusion group was delayed compared to the first ischemic episode which was similar to that of single 10 min ischemic episode. These results suggested that repeated transient occlusion induces less glutamate release from neuronal cell than single occlusion, and the delayed onset time of glutamate release is attributed to endogeneous protective mechanism of ischemic tolerance.

• The Korean Journal of Physiology
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• v.19 no.2
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• pp.173-187
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• 1985

Renal compensatory adaptation caused by ablation of a part of renal mass has long been known in the field of the compensatory renal hypertrophy or hyperplasia. Many reports were found on the chronic mechanisms on the compensatory renal hyperfunction after exclusion of the contralateral kidney. However the mechanism(s) of the acute compensatory hyperfunction after contralateral exclusion has not yet been clarified. In the present experiment, we have tried to prove the possibility of the involvement of the renin-angiotensin system and/or prostaglandin system in the control mechanism of the acute compensatory renal hyperfunction after contralateral kidney exclusion. There were found different responses of the renal hyperfunction by contralateral renal pedicle or ureteral occlusion. Contralateral renal pedicle or ureteral occlusion caused a sustained increases of the urinary volume, sodium and potassium excretion, while the magnitude of the changes was different quantitatively by the maneuvers. Blood collection affected on the acute compensatory renal responses after ureteral as well as renal pedicle occlusion. Plasma prostaglandin $E_2$ level was not changed by the contralateral renal pedicle or ureteral occlusion. Urinary excretion of Prostaglandin $E_2$, the indices of renal prostaglandin biosynthesis, was not changed by the contralateral renal pedicle occlusion, but increased without significance by the contralateral ureteral occlusion. Acute renal compensatory responses after contralateral renal pedicle occlusion were blocked by the pretreatment of indomethacin. Plasma renin activity increased after contralateral ureteral occlusion, but the pattern of the increases was the same as in the time-control group. Plasma renin activity after contralateral renal pedicle occlusion did not change by the time sequence. SQ 20,881, an angiotensin I converting enzyme inhibitor, blunted the contralateral renal responses after the renal pedicle occlusion. Bilateral renal denervation abolished the contralateral renal responses after the renal pedicle occlusion. The above data suggest that there is no direct evidence to support the involvement of the renin-angiotensin system and/or prostaglandin system for the acute compensatory renal hyperfunction after contralateral kidney exclusion, and that the functional changes of the intact kidney may be caused by a humoral substances, or other mechanisms by afferent renal nerve activity originating from the treated kidney.

• The KIPS Transactions:PartA
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• v.15A no.1
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• pp.1-8
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• 2008

An occlusion culling method, one of visibility culling methods, excludes invisible objects or triangles which are covered by other objects. As it reduces computation quantity, occlusion culling is an effective method to handle complex scenes in real-time. But an existing common occlusion culling method, such as hardware occlusion query method, sends objects' data twice to GPU and this causes processing overheads once for occlusion culling test and the other is for rendering. And another existing hardware occlusion culling method, VCBP, can test objects' visibility quickly, but it neither test bounding volume nor return test result to application stage. In this paper, we propose a single pass occlusion culling method which uses temporal and spatial coherency, with effective occlusion culling hardware architecture. In our approach, the hardware performs occlusion culling test rapidly with cache on the rasterization stage where triangles are transformed into fragments. At the same time, hardware sends each primitive's visibility information to application stage. As a result, the application stage reduces data transmission quantity by excluding covered objects using the visibility information on previous frame and hierarchical spatial tree. Our proposed method improved maximum 44%, minimum 14% compared with S&W method based on hardware occlusion query. And the performance is increased 25% and 17% respectively, compared to maximum and minimum performance of CHC method which is based on occlusion culling method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.5
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• pp.1711-1725
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• 2014

Multi-target tracking is the main purpose of many video surveillance applications. Recently, multi-target tracking based on the particle filter method has achieved robust results by using the data association process. However, this method requires many calculations and it is inadequate for real time applications, because the number of associations exponentially increases with the number of measurements and targets. In this paper, to reduce the computational cost of the data association process, we propose a novel multi-target tracking method that excludes particle samples in the overlapped predictive region between the target to track and marginal targets. Moreover, to resolve the occlusion problem, we define an occlusion mode with the normal dynamic mode. When the targets are occluded, the mode is switched to the occlusion mode and the samples are propagated by Gaussian noise without the sampling process of the particle filter. Experimental results demonstrate the robustness of the proposed multi-target tracking method even in occlusion.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.6
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• pp.440-455
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• 2002

The final goal for an orthognathic surgery is a functional and esthetic achievement based on occlusion theory. All the dental treatment should be done with the occlusion in mind, though, they tend to be ignored with no good reason. We cannot think of occlusion without temporomandibular joint because it is the first clue to define an occlusion. As normal occlusion comes from the central tendency of distribution of population, we can get it by examining the population that closely meet the criteria of ideal occlusion. To perform proper occlusal function and to maintain the stability after treatment, the case must be finished in normal occlusion closer to ideal one. Our aim is to achieve the ideal occlusal scheme like the mutually protected occlusion with the best masticatory efficiency and the stability. The facial esthetics are influened by culture, race and the time in which human live. While the occlusal function rarely changes as time goes by, esthetics tend to do from one country to another. Orthodontists and maxillofacial surgeons should have solid sets of treatment goals to achieve the best facial esthetics and the ideal occlusion dictated by the joint. Doing orthognathic surgery, two factors aforementioned should be taken into account to establish the Surgical Treatment Objectives(STO). The doctors who are planning orthognathic surgery need to have a very logical and systematic thought process to make STO. The author examined 28 selected beautiful Korean female adults with normal skeleton with normal occlusion and analyzed the hard and the soft tissue relationship into five parts : dentomaxillary relationship, intermaxillary relationship, posture to hard tissue relationship, facial balance, and posture to soft tissue relationship. This study presents a sequential flow of diagnosis and treatment planning especially for surgical patients and it also can be applied to the nonsurgical patients.

• Journal of the Ergonomics Society of Korea
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• v.30 no.5
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• pp.589-595
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• 2011

Objective: This study compares two visual occlusion methods for the evaluation of in-vehicle interfaces. Background: Visual occlusion is a visual demand measuring technique which uses periodic vision/occlusion cycle to simulate a driving(or mobile) environment. It has been widely used for the evaluation of in-vehicle interfaces. There are two major implementation methods for this technique: (1) occlusion using PLATO(portable liquid crystal apparatus for tachistoscopic occlusion) goggles; (2) occlusion using a software application on a touchscreen device. Method: An experiment was conducted to examine the visual demand of an in-vehicle interface prototype using the goggle-based and the touchscreen-based occlusion methods. Address input and radio tuning tasks were evaluated in the experiment. Results: The results showed that, for the radio tuning task, there were no significant differences in total shutter open time and resumability ratio between the two occlusionconditions. However, it took longer for the participants to input addresses with the touchscreen-based occlusion. Conclusion & Application: The results suggest that touchscreen-based method could be used as an alternative to traditional, gogglebased visual occlusion especially in less demanding visual tasks such as radio tuning.

• Journal of Chest Surgery
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• v.56 no.2
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• pp.108-116
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• 2023

Background: Resuscitative endovascular balloon occlusion of the aorta (REBOA) has recently gained popularity as an adjunct to resuscitation of patients with traumatic shock. However, the effectiveness of REBOA is still debated because of inconsistent indications across centers and the lack of medical records. The purpose of this study was to investigate the effectiveness and feasibility of REBOA by analyzing clinical results from a single center. Methods: This study included 96 patients who underwent REBOA between August 2016 and September 2021 at a regional trauma center according to the center's treatment algorithm for traumatic shock. Medical records, including the time of the decision to conduct the REBOA procedure, time of operation, type of aortic occlusion, and clinical outcomes, were collected prospectively and analyzed retrospectively. Patients were classified by REBOA protocol (group 1, 2, or 3) and survival status (survivor or non-survivor) for analysis. Results: The overall success rate of the procedure was 97.9%, and the survival rate was 32.6%. In survivors, blood pressure was higher than in non-survivors both before the REBOA procedure (p=0.002) and after aortic occlusion (p=0.03). The total aortic occlusion time was significantly shorter (p=0.001) and the proportion of partial aortic occlusion was significantly higher (p=0.014) among the survivors. The non-survivors had more acidosis (p<0.001) and higher lactate concentrations (p<0.001) than the survivors. Conclusion: REBOA may be a feasible bridge therapy for resuscitation of patients with traumatic shock. Prompt and accurate decision-making to perform REBOA followed by damage control surgery could improve survival rates and clinical outcomes.