Ji-hoon Chung - Academia.edu (original) (raw)

Papers by Ji-hoon Chung

The Korean Journal of Crop Science, 2009

Yield monitoring is one of a precision agriculture technology that is used most widely. It is spa... more Yield monitoring is one of a precision agriculture technology that is used most widely. It is spatial variability analysis of yield information that should be attained with yield monitoring system development. This experiment was conducted to evaluate spatial variability of yield and grain moisture content in rice paddy field, and their relationships to rice productivity. It is necessary to minimize sampling interval for accurate yield map making or to control cutting width of rice combine. Considering small rice plots such as ha, optimum size of sampling plot was below 15 m more than 5 m in with and length. In variable rate treatment field, average yield was similar, but yield variation was reduced than conventional field. Gap of yield by another plot in same field was bigger than half of average yield than yield variation was significantly big. Therefore yield measuring flow sensor must be able to measure at least 300 kg/10a more than 1000 kg/10a. Variation of moisture content in same field was not big and spatial dependance did not appear greatly. But, variation between different field is appeared difference according to weather circumstance before harvesting. Change of spatial dependence of yield was not big, because of field variation of moisture content is not big.

Despite of various neurophysiologic monitoring methods under general anesthesia, functional mappi... more Despite of various neurophysiologic monitoring methods under general anesthesia, functional mapping at awake state during brain surgery is helpful for conservation of speech and motor function. But, awake craniotomy in children or adolescents is worrisome considering their emotional friabilities. We present our experience on anesthetic management for awake craniotomy in an adolescent patient. The patient was 16 years old male who would undergo awake craniotomy for removal of brain tumor. Scalp nerve block was done with local anesthetics and we infused propofol and remifentanil with target controlled infusion. The patient endured well and was cooperative before scalp suture, but when surgeon sutured scalp, he complained of pain and was suddenly agitated. We decided change to general anesthesia. Neurosurgeon did full neurologic examinations and there was no neurologic deficit except facial palsy of right side. Facial palsy had improved with time. (Korean J Anesthesiol 2010; 59: S179-S...

This is an open-access article distributed under the terms of the Creative Commons Attribution Li... more This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Despite of various neurophysiologic monitoring methods under general anesthesia, functional mappi... more Despite of various neurophysiologic monitoring methods under general anesthesia, functional mapping at awake state during brain surgery is helpful for conservation of speech and motor function. But, awake craniotomy in children or adolescents is worrisome considering their emotional friabilities. We present our experience on anesthetic management for awake craniotomy in an adolescent patient. The patient was 16 years old male who would undergo awake craniotomy for removal of brain tumor. Scalp nerve block was done with local anesthetics and we infused propofol and remifentanil with target controlled infusion. The patient endured well and was cooperative before scalp suture, but when surgeon sutured scalp, he complained of pain and was suddenly agitated. We decided change to general anesthesia. Neurosurgeon did full neurologic examinations and there was no neurologic deficit except facial palsy of right side. Facial palsy had improved with time. (Korean J Anesthesiol 2010; 59: S179-S...

Agronomy, 2020

This study was conducted to establish a weed management system based on the sequential applicatio... more This study was conducted to establish a weed management system based on the sequential application of pre-emergence (PRE) and post-emergence (POST) herbicides for soybean production in Primorsky krai. Field experiments were conducted for two years in a field located in Bogatyrka, Primorsky krai, Russia (N43°49′, E131°36′). No herbicide application resulted in significant soybean yield loss, 0.03–0.3 t ha−1, which is more than 91.6% yield loss compared with that of the weed-free plot. The PRE application of acetochlor showed good weed control efficacy (greater than 90% weed control) with acceptable soybean safety (less than 10% soybean damage), while the other PRE herbicides performed poorly in terms of weed control. The POST application of bentazon + acifluorfen, bentazon, and imazamox at 30 days after soybean sowing (DAS) showed good weed control efficacy with good soybean safety. Neither the PRE nor POST application alone showed a sufficient soybean yield protection, resulting in ...

This is an open-access article distributed under the terms of the Creative Commons Attribution Li... more This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Agronomy, 2020

This study was conducted to establish a weed management system based on the sequential applicatio... more This study was conducted to establish a weed management system based on the sequential application of pre-emergence (PRE) and post-emergence (POST) herbicides for soybean production in Primorsky krai. Field experiments were conducted for two years in a field located in Bogatyrka, Primorsky krai, Russia (N43°49′, E131°36′). No herbicide application resulted in significant soybean yield loss, 0.03–0.3 t ha−1, which is more than 91.6% yield loss compared with that of the weed-free plot. The PRE application of acetochlor showed good weed control efficacy (greater than 90% weed control) with acceptable soybean safety (less than 10% soybean damage), while the other PRE herbicides performed poorly in terms of weed control. The POST application of bentazon + acifluorfen, bentazon, and imazamox at 30 days after soybean sowing (DAS) showed good weed control efficacy with good soybean safety. Neither the PRE nor POST application alone showed a sufficient soybean yield protection, resulting in ...

Early diagnosis of crop growth at various growth stages will help to make an optimum fertilizatio... more Early diagnosis of crop growth at various growth stages will help to make an optimum fertilization. If we can diagnose crop growth at around the time of topdressing of N fertilizer, N fertilization can be made based on crop growth and target crop yield, which may provide economic and environmental benefits as compared with fixed rate fertilization. In this study we devised methods to diagnose rice growth non-destructively at panicle initiation stage and to determine N topdressing rate. SPAD-502, Field Scout CM1000 and Green Seeker GNDVI were used to diagnose the growth status of rice grown at different soil N fertilities. The values measured by the diagnostic equipments at rice panicle initiation stage were then regressed to rice grain yield. It was found that CM1000 and GNDVI were more efficient than SPAD to diagnose rice growth. Therefore, a multivariate model with CM1000 and GNDVI values was developed to make a decision of N fertilization at rice panicle initiation stage. In a su...

Since understanding on spatial variability of a field is essential to pursue precision agricultur... more Since understanding on spatial variability of a field is essential to pursue precision agricultural technology, a field study for field variability and variable rate fertilization of nitrogen in a direct seeding paddy was attempted. Variable rate application of nitrogen was designed with soil test, and field application was tested in a direct seeding paddy in the Kimje, Jeonbuk, Korea. The grid samples of soil was collected from the field of which unit size was 35 m by 112 m on February before irrigating of the field. Soil organic matter, available phosphate and silicate, and extractable potassium were analyzed. Variable rate fertilizer recommendation maps of nitrogen for high yielding, HY, and low input sustainable agriculture, LISA, were derived based on the soil analysis. Direct seeding of rice was performed for variable rate treatment, VRT, for the experimental plot in 2001 and 2002, and so did for three volunteer farmers' field in 2003. Yield mapping was performed by harves...

RESUMO-As macieiras necessitam de um período de acumulação de frio para a quebra da dormência das... more RESUMO-As macieiras necessitam de um período de acumulação de frio para a quebra da dormência das gemas. Neste estudo, as unidades de frio foram quantificadas por diferentes métodos de cálculo para a região de Vacaria-RS, Brasil, a fim de compará-las com as necessidades de macieiras 'Gala' e 'Fuji'. As unidades de frio foram calculadas para o período de 2000/2009, através dos seguintes métodos: Horas de Frio Ponderadas, Utah, Carolina do Norte, Utah Modificado e Carolina do Norte Modificado. Na região estudada, o número de unidades de frio apresenta alta variabilidade entre os anos, independentemente dos métodos de cálculo. Mesmo em anos com alta disponibilidade de horas de frio, o número de unidades de frio necessárias para a quebra de dormência em macieiras 'Gala' e 'Fuji' não é alcançado, naturalmente. Maio, junho e julho é o principal trimestre para acumular unidades de frio, durante o período de dormência de gemas de macieira. Termos para indexação: Malus domestica, modelos de estimativa de frio, unidades de frio, dormência. CHILL UNITS FOR APPLES TREES IN THE REGION OF VACARIA-RS, BRAZIL ABSTRACT-Apple trees need a period of chill accumulation for breaking the dormancy of buds. In this study, the chilling units were quantified by different calculation methods for the region of Vacaria, in the State of Rio Grande do Sul, Brazil, in order to compare them to the needs of 'Gala' and 'Fuji' apple trees. Chill units were calculated for the period of 2000 to 2009, by the following methods: Weighted Chill Hours, Utah, North Carolina, Modified Utah, and Modified North Carolina. In the studied region, the number of chill units presents high variability among years, regardless of the methods of calculation. Even in years with high availability of chilling hours, the number of chilling units needed for bud break in 'Gala' and 'Fuji' apple trees is not achieved naturally. May, June, and July is the main trimester for accumulating chill units, in the dormancy period of apple buds.

Korean Journal of Crop Science, 2004

Korean journal of anesthesiology, 2010

Pneumocephalus is a condition which usually results from head trauma. It has been known that iatr... more Pneumocephalus is a condition which usually results from head trauma. It has been known that iatrogenic pneumocephalus can occur as a complication of positive pressure mask ventilation during induction of anesthesia or ventilatory care for head trauma patients. We report a case of mask ventilation during anesthesia induction in a 50-year-old male patient with head trauma. Initial pneumocephalus associated with cerebrospinal fluid leakage was diagnosed immediate following head injury involving facial sinuses. He was managed with emergent lumbar drainage and supportive care. Pneumocephalus recurred following positive pressure mask ventilation (PPMV) during anesthesia induction for surgery on the right arm. Recurred pneumocephalus was managed with high flow oxygen and supportive care. Anesthesiologists should be aware of pneumocephalus as a potential complication of PPMV in head trauma patients, even after resolution of previous pneumocephalus.

Korean Journal of Anesthesiology, 2011

Hyperventilation syndrome (HVS) often occurs under stressful conditions, and has been reported du... more Hyperventilation syndrome (HVS) often occurs under stressful conditions, and has been reported during or after anesthesia and operation. HVS, characterized by multiple somatic symptoms and electrolyte imbalances induced by inappropriate hyperventilation, should be managed as an emergency. We report a rare case of HVS during spinal anesthesia. The patient was a previously healthy 51-year-old female without psychogenic conditions. During spinal anesthesia for lower extremity surgery, the patient complained of nausea, headache, paresthesia in the upper extremities and perioral numbness. We found carpal spasm in both hands and flattening of T wave on electrocardiogram (ECG). Emergent arterial blood gas analysis (ABGA) revealed markedly decreased PaCO 2 , hypocalcemia and hypokalemia. We managed the patient with verbal sedation, electrolytes replacement therapy and closed mask inhalation. HVS subsided gradually. We conclude that monitoring for possible HVS during anesthesia is very important for patient safety.

MILCOM 2007 - IEEE Military Communications Conference, 2007

The presence of multiuser interference (MUI) can seriously impact the accuracy of ultra-wideband ... more The presence of multiuser interference (MUI) can seriously impact the accuracy of ultra-wideband (UWB) time delay estimation. This is especially true for the probability of an early false alarm error, which is strongly affected by the peak-to-average ratio (PAR) of the MUI signal. The averaging process used to achieve processing gain can affect the PAR of MUI differently in different multiple access scenarios. In this paper, we examine the effect of CDMA schemes on UWB time-of-arrival estimation performance; we do this by evaluating the PAR of MUI, both semi-analytically and experimentally, for time-hopped and direct sequence multiple access scenarios.

The Korean Journal of Crop Science, 2009

Yield monitoring is one of a precision agriculture technology that is used most widely. It is spa... more Yield monitoring is one of a precision agriculture technology that is used most widely. It is spatial variability analysis of yield information that should be attained with yield monitoring system development. This experiment was conducted to evaluate spatial variability of yield and grain moisture content in rice paddy field, and their relationships to rice productivity. It is necessary to minimize sampling interval for accurate yield map making or to control cutting width of rice combine. Considering small rice plots such as ha, optimum size of sampling plot was below 15 m more than 5 m in with and length. In variable rate treatment field, average yield was similar, but yield variation was reduced than conventional field. Gap of yield by another plot in same field was bigger than half of average yield than yield variation was significantly big. Therefore yield measuring flow sensor must be able to measure at least 300 kg/10a more than 1000 kg/10a. Variation of moisture content in same field was not big and spatial dependance did not appear greatly. But, variation between different field is appeared difference according to weather circumstance before harvesting. Change of spatial dependence of yield was not big, because of field variation of moisture content is not big.

Despite of various neurophysiologic monitoring methods under general anesthesia, functional mappi... more Despite of various neurophysiologic monitoring methods under general anesthesia, functional mapping at awake state during brain surgery is helpful for conservation of speech and motor function. But, awake craniotomy in children or adolescents is worrisome considering their emotional friabilities. We present our experience on anesthetic management for awake craniotomy in an adolescent patient. The patient was 16 years old male who would undergo awake craniotomy for removal of brain tumor. Scalp nerve block was done with local anesthetics and we infused propofol and remifentanil with target controlled infusion. The patient endured well and was cooperative before scalp suture, but when surgeon sutured scalp, he complained of pain and was suddenly agitated. We decided change to general anesthesia. Neurosurgeon did full neurologic examinations and there was no neurologic deficit except facial palsy of right side. Facial palsy had improved with time. (Korean J Anesthesiol 2010; 59: S179-S...

This is an open-access article distributed under the terms of the Creative Commons Attribution Li... more This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Despite of various neurophysiologic monitoring methods under general anesthesia, functional mappi... more Despite of various neurophysiologic monitoring methods under general anesthesia, functional mapping at awake state during brain surgery is helpful for conservation of speech and motor function. But, awake craniotomy in children or adolescents is worrisome considering their emotional friabilities. We present our experience on anesthetic management for awake craniotomy in an adolescent patient. The patient was 16 years old male who would undergo awake craniotomy for removal of brain tumor. Scalp nerve block was done with local anesthetics and we infused propofol and remifentanil with target controlled infusion. The patient endured well and was cooperative before scalp suture, but when surgeon sutured scalp, he complained of pain and was suddenly agitated. We decided change to general anesthesia. Neurosurgeon did full neurologic examinations and there was no neurologic deficit except facial palsy of right side. Facial palsy had improved with time. (Korean J Anesthesiol 2010; 59: S179-S...

Agronomy, 2020

This study was conducted to establish a weed management system based on the sequential applicatio... more This study was conducted to establish a weed management system based on the sequential application of pre-emergence (PRE) and post-emergence (POST) herbicides for soybean production in Primorsky krai. Field experiments were conducted for two years in a field located in Bogatyrka, Primorsky krai, Russia (N43°49′, E131°36′). No herbicide application resulted in significant soybean yield loss, 0.03–0.3 t ha−1, which is more than 91.6% yield loss compared with that of the weed-free plot. The PRE application of acetochlor showed good weed control efficacy (greater than 90% weed control) with acceptable soybean safety (less than 10% soybean damage), while the other PRE herbicides performed poorly in terms of weed control. The POST application of bentazon + acifluorfen, bentazon, and imazamox at 30 days after soybean sowing (DAS) showed good weed control efficacy with good soybean safety. Neither the PRE nor POST application alone showed a sufficient soybean yield protection, resulting in ...

This is an open-access article distributed under the terms of the Creative Commons Attribution Li... more This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Agronomy, 2020

This study was conducted to establish a weed management system based on the sequential applicatio... more This study was conducted to establish a weed management system based on the sequential application of pre-emergence (PRE) and post-emergence (POST) herbicides for soybean production in Primorsky krai. Field experiments were conducted for two years in a field located in Bogatyrka, Primorsky krai, Russia (N43°49′, E131°36′). No herbicide application resulted in significant soybean yield loss, 0.03–0.3 t ha−1, which is more than 91.6% yield loss compared with that of the weed-free plot. The PRE application of acetochlor showed good weed control efficacy (greater than 90% weed control) with acceptable soybean safety (less than 10% soybean damage), while the other PRE herbicides performed poorly in terms of weed control. The POST application of bentazon + acifluorfen, bentazon, and imazamox at 30 days after soybean sowing (DAS) showed good weed control efficacy with good soybean safety. Neither the PRE nor POST application alone showed a sufficient soybean yield protection, resulting in ...

Early diagnosis of crop growth at various growth stages will help to make an optimum fertilizatio... more Early diagnosis of crop growth at various growth stages will help to make an optimum fertilization. If we can diagnose crop growth at around the time of topdressing of N fertilizer, N fertilization can be made based on crop growth and target crop yield, which may provide economic and environmental benefits as compared with fixed rate fertilization. In this study we devised methods to diagnose rice growth non-destructively at panicle initiation stage and to determine N topdressing rate. SPAD-502, Field Scout CM1000 and Green Seeker GNDVI were used to diagnose the growth status of rice grown at different soil N fertilities. The values measured by the diagnostic equipments at rice panicle initiation stage were then regressed to rice grain yield. It was found that CM1000 and GNDVI were more efficient than SPAD to diagnose rice growth. Therefore, a multivariate model with CM1000 and GNDVI values was developed to make a decision of N fertilization at rice panicle initiation stage. In a su...

Since understanding on spatial variability of a field is essential to pursue precision agricultur... more Since understanding on spatial variability of a field is essential to pursue precision agricultural technology, a field study for field variability and variable rate fertilization of nitrogen in a direct seeding paddy was attempted. Variable rate application of nitrogen was designed with soil test, and field application was tested in a direct seeding paddy in the Kimje, Jeonbuk, Korea. The grid samples of soil was collected from the field of which unit size was 35 m by 112 m on February before irrigating of the field. Soil organic matter, available phosphate and silicate, and extractable potassium were analyzed. Variable rate fertilizer recommendation maps of nitrogen for high yielding, HY, and low input sustainable agriculture, LISA, were derived based on the soil analysis. Direct seeding of rice was performed for variable rate treatment, VRT, for the experimental plot in 2001 and 2002, and so did for three volunteer farmers' field in 2003. Yield mapping was performed by harves...

RESUMO-As macieiras necessitam de um período de acumulação de frio para a quebra da dormência das... more RESUMO-As macieiras necessitam de um período de acumulação de frio para a quebra da dormência das gemas. Neste estudo, as unidades de frio foram quantificadas por diferentes métodos de cálculo para a região de Vacaria-RS, Brasil, a fim de compará-las com as necessidades de macieiras 'Gala' e 'Fuji'. As unidades de frio foram calculadas para o período de 2000/2009, através dos seguintes métodos: Horas de Frio Ponderadas, Utah, Carolina do Norte, Utah Modificado e Carolina do Norte Modificado. Na região estudada, o número de unidades de frio apresenta alta variabilidade entre os anos, independentemente dos métodos de cálculo. Mesmo em anos com alta disponibilidade de horas de frio, o número de unidades de frio necessárias para a quebra de dormência em macieiras 'Gala' e 'Fuji' não é alcançado, naturalmente. Maio, junho e julho é o principal trimestre para acumular unidades de frio, durante o período de dormência de gemas de macieira. Termos para indexação: Malus domestica, modelos de estimativa de frio, unidades de frio, dormência. CHILL UNITS FOR APPLES TREES IN THE REGION OF VACARIA-RS, BRAZIL ABSTRACT-Apple trees need a period of chill accumulation for breaking the dormancy of buds. In this study, the chilling units were quantified by different calculation methods for the region of Vacaria, in the State of Rio Grande do Sul, Brazil, in order to compare them to the needs of 'Gala' and 'Fuji' apple trees. Chill units were calculated for the period of 2000 to 2009, by the following methods: Weighted Chill Hours, Utah, North Carolina, Modified Utah, and Modified North Carolina. In the studied region, the number of chill units presents high variability among years, regardless of the methods of calculation. Even in years with high availability of chilling hours, the number of chilling units needed for bud break in 'Gala' and 'Fuji' apple trees is not achieved naturally. May, June, and July is the main trimester for accumulating chill units, in the dormancy period of apple buds.

Korean Journal of Crop Science, 2004

Korean journal of anesthesiology, 2010

Pneumocephalus is a condition which usually results from head trauma. It has been known that iatr... more Pneumocephalus is a condition which usually results from head trauma. It has been known that iatrogenic pneumocephalus can occur as a complication of positive pressure mask ventilation during induction of anesthesia or ventilatory care for head trauma patients. We report a case of mask ventilation during anesthesia induction in a 50-year-old male patient with head trauma. Initial pneumocephalus associated with cerebrospinal fluid leakage was diagnosed immediate following head injury involving facial sinuses. He was managed with emergent lumbar drainage and supportive care. Pneumocephalus recurred following positive pressure mask ventilation (PPMV) during anesthesia induction for surgery on the right arm. Recurred pneumocephalus was managed with high flow oxygen and supportive care. Anesthesiologists should be aware of pneumocephalus as a potential complication of PPMV in head trauma patients, even after resolution of previous pneumocephalus.

Korean Journal of Anesthesiology, 2011

Hyperventilation syndrome (HVS) often occurs under stressful conditions, and has been reported du... more Hyperventilation syndrome (HVS) often occurs under stressful conditions, and has been reported during or after anesthesia and operation. HVS, characterized by multiple somatic symptoms and electrolyte imbalances induced by inappropriate hyperventilation, should be managed as an emergency. We report a rare case of HVS during spinal anesthesia. The patient was a previously healthy 51-year-old female without psychogenic conditions. During spinal anesthesia for lower extremity surgery, the patient complained of nausea, headache, paresthesia in the upper extremities and perioral numbness. We found carpal spasm in both hands and flattening of T wave on electrocardiogram (ECG). Emergent arterial blood gas analysis (ABGA) revealed markedly decreased PaCO 2 , hypocalcemia and hypokalemia. We managed the patient with verbal sedation, electrolytes replacement therapy and closed mask inhalation. HVS subsided gradually. We conclude that monitoring for possible HVS during anesthesia is very important for patient safety.

MILCOM 2007 - IEEE Military Communications Conference, 2007

The presence of multiuser interference (MUI) can seriously impact the accuracy of ultra-wideband ... more The presence of multiuser interference (MUI) can seriously impact the accuracy of ultra-wideband (UWB) time delay estimation. This is especially true for the probability of an early false alarm error, which is strongly affected by the peak-to-average ratio (PAR) of the MUI signal. The averaging process used to achieve processing gain can affect the PAR of MUI differently in different multiple access scenarios. In this paper, we examine the effect of CDMA schemes on UWB time-of-arrival estimation performance; we do this by evaluating the PAR of MUI, both semi-analytically and experimentally, for time-hopped and direct sequence multiple access scenarios.