• Journal of the Society of Naval Architects of Korea
• /
• v.33 no.4
• /
• pp.1-14
• /
• 1996

Especially in the case of a full form ship, the stability on course can be considered to become severest among 4 items of criteria in Interim Standards for Ship Maneuverability adopted by IMO in 1993. The purpose of this study is to find some ideas for the improvement of stability on course through changes in rudder area with reference to span distance. In this paper, we established the formula on the relation between the experimental constants relevant to rudder normal force and hydrodynamic derivatives of hull-propeller-rudder system. We carried out various kinds of captive model test relevant to rudder normal force etc., and evaluated hydrodynamic derivatives of hull-propeller-rudder system, and analyzed the stability on course with the parameter of changes in rudder area. Furthermore, we also discussed effects of changes in rudder area on maneuvering performance including stability on course, based on computer simulation. As a result, it is clarified that there is a possibility that stability on course may become bad through an increase of rudder area. The reason for the bad stability on course is that the void space between the upper edge of rudder and the lower part of stern overhang decreases. This space change exerts a great influence on straightening coefficient of incoming flow to rudder in maneuvering motion, which has close relation to stability on course.

• Journal of Veterinary Clinics
• /
• v.26 no.6
• /
• pp.659-662
• /
• 2009

The Korea Institute of Oriental White Stork Rehabilitation Research (KIOWSRR) is breeding oriental white storks for residential rehabilitation in South Korea. Three oriental white storks were referred with anorexia and depression. Two storks were died before examinations and one stork was died after 1 day of fluid therapy. On necropsy, salmon-colored subcutaneous and visceral fats were examined in all storks. Multiple focal necroses on liver surface were also examined. In gizzards, many gravels and grasses were severely tangled; therefore, it produced a large mass that blocked digestive system of the storks. Small intestinal segments of the stork, which was dead after the fluid therapy, were severely adhesive. On histopathology, diffuse necroses with/without inflammation were examined in the liver, gizzard and intestine in all storks. Bile stasis was additionally examined in the liver. According to the results of the examinations, all storks were diagnosed as gizzard impaction caused by parorexia.

• Journal of Veterinary Clinics
• /
• v.27 no.5
• /
• pp.614-617
• /
• 2010

A 3-year-old, female spotted hyena (Crocuta crocuta) was referred with dystocia. The hyena had been in labor for over 5 days, but she failed to expel the infant. The blood biochemistry profiles showed severe azotemia. During caesarian section, we confirmed that the uterus had expanded and contained 1 dead, decayed infant, which compress the urethra, leading to the expansion of the urinary bladder and that the dead fetus was nearly 3 kg in weight (approximately 5% of the maternal weight). Thus, we confirmed that the dystocia caused by oversized fetus and malposture, and the severe azotemia resulted in compression of the urethra by fetus in the hyena. This report is the first to show that the dystocia can induce postrenal azotemia in female spotted hyenas.

• Journal of Veterinary Clinics
• /
• v.30 no.3
• /
• pp.214-217
• /
• 2013

A 3-year-old intact female hedgehog (Atelerix albiventris) was presented for evaluation of mandibular swelling. Fine needle aspiration of swollen mandibular was performed and smears were stained with Romanowsky type stain for cytological evaluation. Smears were highly cellular with predominance of variably shaped keratinized or non keratinized squamous cells with low numbers of spindloid to abnormally elongated cells. Cytologic impression was squamous cell carcinoma. The mass was surgically removed for histological examination. Microscopically tortuous and anastomosing delicate to broad pegs and nests of neoplastic squamous epithelial cells were supported by a moderate collagenous and spindloid fibroblast stroma. Tumor cells had moderate anisocytosis and mild anisokaryosis and range from moderately to well keratinized, with areas of intratumoral acantholysis accompanied by mixed stromal lymphoplasmacytic, neutrophilic inflammation. The mitotic index is 2-3 per high-power field. Tumor cells were expanding the subcutis subjacent to the layer of skeletal muscle and incorporating the osseous tissue fragments. The final diagnosis was squamous cell carcinoma. The patient survived three months after surgery without any further medical treatments.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.40 no.3
• /
• pp.51-59
• /
• 2012

Zoological parks are considered to be a recreational place for family outings and most importantly the starting place of contact with animals in the modem society. Due to environmental threats and the loss of wildlife habitats, the zoos have significant roles to play in education, research and conservation in addition to the traditional role-entertainment, but research on zoos and their visitors is very limited in Korea. The present study surveyed that the zoo visitors' perceptions of the role of zoos, satisfaction, and behaviors in 6 public zoos, during which 730 zoo visitors were interviewed. The results indicated that the zoos represent an opportunity for family-based trips, enjoyment with family or friends and education that are the primary motives for visiting the zoos. The findings demonstrate that respondents considered the four main roles of zoos namely conservation, education, entertainment, and research to be important and recognize its value for conservation and environmental education. The determinants of satisfaction of zoo visitors were ease of visibility, welfare of captive animals, and the availability of information. Most respondents believed that naturalistic exhibits and animal welfare were very important. In order to reinforce the roles of the zoo in modem society, multidisciplinary efforts are needed to improve the animal welfare, replicate native habitats, and develop various education programs.

• Animal cells and systems
• /
• v.15 no.2
• /
• pp.161-168
• /
• 2011

Siberian chipmunks, Tamias sibiricus, are one of several popular companion animals found in the pet shops of South Korea. At present, however, there have been no studies done in South Korea examining their origin even though they could be potential carriers of zoonotic diseases, and are a species of concern for efficient conservation and management strategies. Sequences of the mitochondrial cytochrome b gene (1140 bp) were determined to investigate the origin of Siberian chipmunks sold in four South Korean pet shops through comparison with sequence data from animals of known locality. Nine Siberian chipmunks were collected from pet shops in South Korea, which resulted in nine haplotypes. One (AR) of these coincided with the haplotype previously described. Phylogenetic and network analyses using 53 haplotypes including 45 haplotypes from GenBank showed three phylogenetic groups in South Korea, almost concordant to locality, designated as northern, central, and southern parts as described in a previous study. Of the nine individuals examined from the pet shops, eight were clustered into the northern phylogroup but one (cgrb9153) was grouped with the southern phylogroup, implying that at least the Siberian chipmunks examined in this study did not originate from other countries. It is likely that most individuals sold in the pet shops of Seoul were caught in the wild in Gyeonggi-do and Gangwon-do, or are maternal descendants of captive-bred individuals originating from the northern part of South Korea. It is recommended that conservation and management units of Korean chipmunks should be examined in further detail.

• Korean Journal of Ornithology
• /
• v.25 no.2
• /
• pp.69-76
• /
• 2018

Sexual dimorphism in birds refers to male-female differences in body size, plumage, color and/or behavior. In general, many seabirds, including the family of Laridae, are monomorphic in plumage-color, which makes the determination of sex difficult in the field because both parents also tend to share a great portion of parental care. The development of an inexpensive sexing tool facilitates understanding the degree of sex-specific parental care in the evolution of the life history. Here, we developed a non-invasive method for the determination of sex using the bill-head morphometric of known captive pairs and applied this tool to wild pairs to document factors underlying male-female parental care during the incubation period of Saunders's gulls (Saundersilarus saundersi). Males exhibited relatively larger bill-head ratios than their mates within naturally formed pairs in captivity, resulting in the determination of sex in12 wild pairs at the nest during the incubation period. Males and females equally shared the incubation role during the daytime, attending the nest at a high rate of 95%. However, the male's proportion of nest attentiveness greatly increased with time towards sunset, presumably reflecting the male duty for nighttime incubation. The present study provides a non-invasive method for the determination of sex in a monomorphic seagull species and highlights how male-female incubation behavior is associated with time of the day, rather than other ecological conditions.

• The Journal of Korean Institute of Information Technology
• /
• v.16 no.11
• /
• pp.51-59
• /
• 2018

The Multi-Mission Unmanned Surface Vehicle(MMUSV), which is manufactured using glass Fiber Reinforced Plastic(FRP) material, is designed to perform a surveillance and reconnaissance on the sea. Various navigation sensors, such as RADAR, RIDAR, camera, are mounted on a mast to perform an autonomous navigation. And a dummy gun is mounted on the deck of the MMUSV for a target tracking and disposal. It is necessary to analyze a strength for structures mounted on the deck because the MMUSV performs missions under a severe sea state. In this paper, a strength analysis of the mast structure is performed on static loads and lateral external loads to verify an adequacy of the designed mast through a series of simulations. Based on the results of captive model tests, a strength analysis for a heave motion of the mast structure is conducted using a simulation tool. Also a simulation and fatigue test for a mounting part between the MMUSV and the dummy gun are performed using a specimen. The simulation and test results are represented that a structure of the mast and mounting part of the dummy gun are appropriately designed.he impact amount are performed through simulation and experiments.

• The Journal of the Acoustical Society of Korea
• /
• v.38 no.1
• /
• pp.56-65
• /
• 2019

The Indo-Pacific bottlenose dolphins (Tursiops aduncus) are a toothed whale using echolocation clicks and have been studied continuously abroad. However, most studies on this whale's clicks were performed about captive animals and, in Korea, only the studies of the whistle sounds of this animal were done. In this paper, acoustic characteristics of clicks were analyzed about the free-ranging Indo-Pacific bottlenose dolphins living in the coast of the Jeju Island. Acoustic parameters such as signal duration, 1st and 2nd peak frequency, 3 dB and 10 dB bandwidth for acoustic characteristics were calculated and compared with those of Australian species. As a result, the signal durations had average of $38{\mu}s$ and most clicks were within range of $20{\mu}s-60{\mu}s$. The two types of bandwidths showed both narrowband and broadband characteristics, and bimodal signal characteristics were confirmed through the 1st peak frequencies(average of $96kHz{\pm}18kHz$) and the 2nd peak frequencies(average of $69kHz{\pm}19kHz$).

• Journal of Navigation and Port Research
• /
• v.46 no.3
• /
• pp.168-178
• /
• 2022

In this study, the resistance test, the vertical static angle of the attack test and VPMM test will be conducted to estimate the maneuverability of underwater vehicles with ahead propeller. The vertical static test will be conducted within the range of -40deg to 40deg, to investigate the cross-flow drag at high incidence angles. The tests will be conducted by dividing the propeller rotation into a case in which the propeller rotates at a specific rpm, and a case in which the propeller rotates naturally, according to the towing speed. Hydrodynamic coefficients of vertical direction will be estimated by the captive model tests. Additionally, the vertical dynamic stability index based on estimated hydrodynamic coefficients will be calculated and the impact of the propeller revolution state on the index will be investigated. The results are expected to be used as reference test data for underwater vehicles with ahead propeller.